Communication control equipment and communication control method

ABSTRACT

A communication control system lessens the burden (load) of repeaters and has a reduced number of development steps. Data of the ATM (Asynchronous Transfer Mode) signaling protocol standard that is delivered to an ATM/1394 repeater  3  (FIG.  4,  for example) through an ATM network  2  from an ATM terminal  1  is converted to data of the IEEE 1394 transmission standard by an ASEL (ATM over IEEE 1394 Serial bus Emulation Layer)  31  (see FIG.  54,  for example). The data of the IEEE 1394 standard transmitted to a 1394 terminal  4  is converted into data of the ATM standard by an ASEL  32.  Advantageously, using the inventive ASEL avoids the need for an original (special-purpose) signaling protocol (FIG.  3 ) that would otherwise be required between the repeater and the terminal(s)  4.

This is a continuation of application Ser. No. 08/973,175, filed Dec. 3,1997 and now U.S. Pat. No. 6,115,392, which is a 371 of PCT/JP97/01178filed Apr. 4, 1997.

TECHNICAL FIELD

This invention relates to a communication control equipment and acommunication control method, and more particularly to a communicationcontrol equipment and a communication control method suitable when used,e.g., in video on demand system, etc. for providing multimedia data.

BACKGROUND ART

FIG. 1 shows one example of conceivable configuration of VOD (Video OnDemand) system using the ATM (Asynchronous Transfer Mode) network at thebackbone side and the IEEE (The Institute of Electrical and ElectronicEngineers, Inc.) 1394 serial bus (IEEE 1394 Standards Draft 8.0v2) atthe front end side.

An ATM terminal 1 is a server for storing video data, etc., and isconnected to an ATM network 2 through UNI (User-Network Interface) tomake an offer of video data to 1394 terminals 4-1 to 4-7 (hereinafterreferred to as 1394 terminals 4 as occasion may demand when there is nonecessity to individually discriminate between 1394 terminals 4-1 to4-7). An ATM/1394 repeater 3 is connected to the ATM network 2 throughUNI and serves to receive video data transmitted from the ATM terminal 1via the ATM network 2 to make an offer thereof to the 1394 terminals 4through the IEEE 1394 serial bus. The 1394 terminals 4 receive videodata offered through the IEEE 1394 serial bus from the ATM/1394 repeater3 to display them on respective display units such as CRT or LCD, etc.

In this VOD system, when the ATM terminal 1 carries out communicationbetween the ATM terminal 1 and any 1394 terminal 4, protocol peculiar toATM must be entirely terminated at the ATM/1394 repeater 3.

In the case where IP over ATM (hereinafter abbreviated as IP/ATM) isused as the standard protocol when, e.g., the ATM terminal 1 carries outtransmission/reception of IP (Internet Protocol) packet between the ATMterminal 1 and the 1394 terminal 4, protocol stacks of the U (User)plane and the C (Control) plane of end to end are caused to respectivelyundergo layout as shown in FIGS. 2 and 3.

Namely, as shown in FIG. 2, the protocol stack of the U plane of the ATMnetwork 2 consists of PHY (physical) layer and ATM layer. Accordingly,the protocol stack of the U plane of the ATM terminal 1 includes PHYlayer and ATM layer in correspondence with the ATM network 2, andincludes IP/ATM layer and IP layer for carrying outtransmission/reception of IP packet. Further, between the ATM layer andthe IP/ATM layer, the protocol stack of the U plane of the ATM terminal1 includes AAL (ATM Adaptation Layer) 5 for carrying outmatching/adjustment between data unit (user information from 1 byte upto 64 k bytes) of the high order (upper) application (IP/ATM layer) anduser information of 48 bytes handled by cell in a unified manner.

In the protocol stack of the U plane of the ATM/1394 repeater 3, the ATMnetwork 2 side is caused to be of structure similar to the ATM terminal1. Namely, this protocol stack consists of PHY layer, ATM layer, AAL5layer, IP/ATM layer and IP layer. On the other hand, the 1394 terminal 4side is caused to be of structure similar to the protocol stack of the1394 terminal 4 and consists of 1394 PHY layer, 1394 LINK layer and IPlayer. There is no layer corresponding to the IP/ATM layer of the ATMnetwork 2 side (Therefore, labeled null in FIG. 2) (It is to be notedthat it is conceivable to place (allocate) protocol like IP/1394). Theprotocol stack of the U plane of the 1394 terminal 4 consists of 1394PHY layer, 1394 LINK layer and IP layer.

Moreover, as shown in FIG. 3, the protocol stack of the C plane of theATM terminal 1 consists of PHY layer, ATM layer, AAL5 layer, SSCF(Service Specific Coordination Function) (ITU (InternationalTelecommunication Union)-TQ.2130)+SSCOP (Service Specific ConnectionOriented Prtocol) (ITU-TQ.2110) layer, and Q.2931 (ITU-TQ.2931) layer.The protocol stack of the C plane of the ATM network 2 is caused to beof structure similar to the case of the ATM terminal 1.

In the protocol stack of the C plane of the ATM/1394 repeater 3, the ATMnetwork 2 side is caused to be of structure similar to the case of theATM terminal 1 and the ATM network 2. On the other hand, the 1394terminal 4 side is caused to be of structure similar to the protocolstack of the 1394 terminal 4, and consists of 1394 PHY layer, 1394 LINKlayer and Original Signaling Protocol layer. The protocol stack of the Cplane of the 1394 terminal 4 consists of 1394 PHY layer, 1394 LINK layerand Original Signaling Protocol layer.

Since the concept of VPC (Virtual Pass Connection)/VCC (Virtual ChannelConnection) does not exist between the ATM/1394 repeater 3 and the 1394terminal 4 as shown in FIG. 2, it is conceivable to carry out handlingof packet of the U plane by IP header. In that case, for the ATM/1394repeater 3, routing function by IP is required.

Moreover, since the signaling protocol (Q.2931 layer and SSCF+SSCOPlayer) used in UNI of the ATM network 2 cannot be applied between theATM/1394 repeater 3 and the 1394 terminal 4 as shown in FIG. 3, it isnecessary to peculiarly design original signaling protocol correspondingthereto to use such protocol.

However, in the ATM/1394 repeater 3, in the case where handling ofpacket of the U plane is carried out by using the routing function byIP, it is necessary to copy the entirety of IP packet including data toread therefrom information necessary for routing, resulting in theproblem that burden (load) applied to the ATM/1394 repeater 3 is great.

In addition, there occurs the necessity of developing the originalsignaling protocol used between the ATM/1394 repeater 3 and the 1394terminal 4 from the first stage. To realize this, great amount ofinvestment is required, resulting in the problem that such approach wasnot realistic.

DISCLOSURE OF THE INVENTION

This invention has been made in view of such circumstances, and itsobject is to have ability to lessen the burden of the repeater whentransmission/reception of data of different transmission standards iscarried out between terminals through the repeater, and to reduce thedevelopment steps of the system.

A communication control equipment according to this invention comprises:first converting means for converting data of a second transmissionstandard received through a repeater into data of a first transmissionstandard; and second converting means for converting predetermined dataof the first transmission standard into data of the second transmissionstandard.

A communication control method according to this invention comprises: astep of converting data of a first transmission standard receivedthrough a repeater into data of a second transmission standard; and astep of converting predetermined data of the second transmissionstandard into data of the first transmission standard.

A communication control equipment according to this invention comprises:first converting means for converting data of a first transmissionstandard transmitted from a first terminal into data of a secondtransmission standard; second converting means for converting data ofthe second transmission standard transmitted from a second terminal intodata of the first transmission standard; and processing means forprocessing, by the same signaling protocol as signaling protocol thatthe first terminal has, the data of the first transmission standardtransmitted from the first terminal and the data of the firsttransmission standard converted by the second converting means.

A communication control method according to this invention comprises: afirst conversion step of converting data of a first transmissionstandard transmitted from a first terminal into data of a secondtransmission standard; a second conversion step of converting data ofthe second transmission standard transmitted from a second terminal intodata of the first transmission standard; and a processing step ofprocessing, by the same signaling protocol as signaling protocol thatthe first terminal has, the data of the first transmission standardtransmitted from the first terminal and the data of the firsttransmission standard converted by the second converting means.

A communication control equipment according to this invention is adaptedso that the repeater comprises first converting means for convertingdata of a first transmission standard transmitted from the firstterminal into data of a second transmission standard, and secondconverting means for converting data of the second transmission standardtransmitted from the second terminal into data of the first transmissionstandard; and the second terminal comprises third converting means forconverting the data of the second transmission standard which has beencaused to undergo transmission (transmitted) from the repeater into dataof the first transmission standard, and fourth converting means forconverting predetermined data of the first transmission standard intodata of the second transmission standard.

A communication control method according to this invention is adapted sothat processing procedure by the repeater comprises a step of convertingdata of a first transmission standard transmitted from a first terminalinto data of a second transmission standard to carry out transmissionthereof (transmit it) to a second terminal, and a step of convertingdata of the second transmission standard transmitted from the secondterminal into data of the first transmission standard to carry outtransmission thereof (transmit it) to the first terminal; and processingprocedure by the second terminal comprises a step of converting the dataof the second transmission standard which has been caused to undergotransmission (transmitted) through the repeater into data of the firsttransmission standard, and a step of converting predetermined data ofthe first transmission standard into data of the second transmissionstandard to carry out transmission thereof (transmit it) to therepeater.

A communication control equipment according to this invention comprisessetting means for setting, in advance, by using predetermined controlcommands, communication channel (path) for transferring data of thetransmission standard that the terminal and any other terminal carry outtransmission/reception therebetween through the repeater or directlytherebetween.

A communication control method according to this invention comprises astep of setting, in advance, by using predetermined control commands,communication channel (path) for transferring data of the transmissionstandard that the terminal and any other terminal carry outtransmission/reception therebetween through the terminal or directlytherebetween.

In the communication control equipment according to this invention, thefirst converting means converts data of the first transmission standardreceived through the repeater into data of the second transmissionstandard, and the second converting means converts predetermined data ofthe second transmission standard into data of the first transmissionstandard.

In the communication control method according to this invention, data ofthe first transmission standard received through the repeater isconverted into data of the second transmission standard, andpredetermined data of the second transmission standard is converted intodata of the first transmission standard.

In the communication control equipment and the communication controlmethod according to this invention, data of the first transmissionstandard transmitted from the first terminal and data of the firsttransmission standard converted by the second converting means areprocessed by the same signaling protocol as the signaling protocol thatthe first terminal has.

In the communication control equipment according to this invention, atthe repeater, the first converting means converts data of the firsttransmission standard transmitted from the first terminal into data ofthe second transmission standard, and the second converting meansconverts data of the second transmission standard transmitted from thesecond terminal into data of the first transmission standard. Inaddition, at the second terminal, the third converting means convertsdata of the second transmission standard which has been caused toundergo transmission (transmitted) from the repeater into data of thefirst transmission standard, and the fourth converting means convertspredetermined data of the first transmission standard into data of thesecond transmission standard.

In the communication control method according to this invention, therepeater converts data of the first transmission standard transmittedfrom the first terminal into data of the second transmission standard tocarry out transmission thereof (transmit it) to the second terminal, andconverts data of the second transmission standard transmitted from thesecond terminal into data of the first transmission standard to carryout transmission thereof (transmit it) to the second terminal. Thesecond terminal converts the data of the second transmission standardwhich has been caused to undergo transmission (transmitted) through therepeater into data of the first transmission standard, and convertspredetermined data of the first transmission standard into data of thesecond transmission standard to carry out transmission thereof (transmitit) to the repeater.

In the communication control equipment and the communication controlmethod according to this invention, the communication channel (path) fortransferring data of the transmission standard that the terminal and anyother terminal carry out transmission/reception is set in advance byusing predetermined control commands therebetween through the repeateror directly therebeteen.

While the embodiments of this invention will now be described, thefeatures of this invention will be described in a manner as below priorto the description of the embodiments of this invention in the statewhere corresponding embodiments (one example in this case) are added tothe inside of parentheses after respective means in order to clarify thecorrespondence relationship between respective means of the inventionsdescribed in the patent claims and the following embodiments.

A communication control equipment according to this invention comprisesfirst converting means (e.g., ASEL 32 of FIG. 54) for converting data ofthe second transmission standard (e.g., IEEE 1394 standard) receivedthrough the repeater (e.g., ATM/1394 repeater 3 of FIG. 4) into data ofthe first transmission standard (e.g., ATM standard), and secondconverting means (e.g., ASEL 32 of FIG. 54) for converting predetermineddata of the first transmission standard into data of the secondtransmission standard.

The communication control equipment according to this invention furthercomprises processing means (e.g., layer 36 of FIG. 55) for processingdata of the first transmission standard by the same signaling protocolas signaling protocol that the terminal has.

A communication control equipment according to this invention comprisesfirst converting means (e.g, ASEL 33 of FIG. 55) for converting data ofthe first transmission standard (e.g., standard of ATM) transmitted fromthe first terminal (e.g., ATM terminal 1 of FIG. 4) into data of thesecond transmission standard (e.g., standard of IEEE 1394), secondconverting means (e.g., ASEL 33 of FIG. 55) for converting data of thesecond transmission standard transmitted from the second terminal (e.g.,1394 terminal 4-1 of FIG. 4) into data of the first transmissionstandard, and processing means (e.g., layer 35 of FIG. 55) forprocessing, by the same signaling protocol as the signaling protocolthat the first terminal has, the data of the first transmission standardtransmitted from the first terminal and the data of the firsttransmission standard converted by the second converting means.

The communication control equipment according to this invention furthercomprises repeater means (e.g., ASEL 31 of FIG. 54) such that in thecase where plural second terminals (e.g., 1394 terminals 22-1 and 23-1of FIG. 4) are connected onto different transmission channels (paths) ofthe second transmission standard, it repeats data of the secondtransmission standard in the U-plane which is caused to undergotransmission/reception between the plural second terminals.

The communication control equipment according to this invention furthercomprises repeater means (e.g., ASEL 31 of FIG. 54) such that in thecase where plural second terminals (e.g., 1394 terminals 22-1 and 22-2of FIG. 4) are connected onto the same transmission channel (path) ofthe second transmission standard, it allows data of the secondtransmission standard in the U-plane which is caused to undergotransmission/reception between the plural second terminals to besubstantially therethrough to repeat it.

A communication control equipment according to this invention is suchthat the repeater (e.g., ATM/1394 repeater 3 of FIG. 4) comprises firstconverting means (e.g., ASEL 31 of FIG. 54) for converting data of thefirst transmission standard (e.g., standard of ATM) transmitted from thefirst terminal (e.g., ATM terminal 1 of FIG. 4) into data of the secondtransmission standard (e.g., standard of IEEE 1394), and secondconverting means (e.g., ASEL 31 of FIG. 54) for converting data of thethe second transmission standard transmitted from the second terminal(e.g., 1394 terminal 4-1 of FIG. 4) into data of the first transmissionstandard; and the second terminal comprises third converting means(e.g., ASEL 32 of FIG. 54) for converting data of the secondtransmission standard which has been caused to undergo transmission(transmitted) from the repeater into data of the first transmissionstandard, and fourth converting means for converting predetermined dataof the first transmission standard into data of the second transmissionstandard.

A communication control equipment according to this invention comprisessetting means for setting, in advance, by predetermined controlcommands, communication channel (path) for transferring data of thetransmission standard that the terminal (e.g., 1394 terminal 4-1 of FIG.4) and another terminal (e.g., 1394 terminal 4-2 of FIG. 4) carry outtransmission/reception therebetween through the repeater (e.g., ATM/1394repeater 3 of FIG. 4) or directly therebetween.

It is to be noted that the aforesaid description does not mean that therespective means are limited to the above-described components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing an example of the configuration of aconventional VOD system.

FIG. 2 is a view showing protocol stack of U plane conceivable whenIP/ATM is used.

FIG. 3 is a view showing protocol stack of C plane conceivable whenIP/ATM is used.

FIG. 4 is a view showing an example of the configuration of VOD systemto which a communication control equipment of this invention is applied.

FIG. 5 is a view for explaining the relationship of ASEL-UNI.

FIG. 6 is a view showing layer related diagram of ASEL.

FIG. 7 is a view showing insertion field of ASEL-PDU.

FIG. 8 is a view showing format common to all AAL types of ASEL-PDU andcoding example thereof.

FIG. 9 is a view showing format and coding example of ASEL-PDU (AAL5Type).

FIG. 10 is a view showing format and coding example of ASEL-PDU (AAL0Type).

FIG. 11 is a view for explaining the relationship between ASEL-CMI andASEL-UNI.

FIG. 12 is a view for explaining status transition of ASEL-CME at Userside.

FIG. 13 is a view for explaining status transition of ASEL-CME atNetwork side.

FIG. 14 is a view showing format of field common to ASEL-CMP message.

FIG. 15 is a view showing format of WakeUp message.

FIG. 16 is a view showing format of ActReq message.

FIG. 17 is a view showing format of ActAck message.

FIG. 18 a view showing format of IsoReq message.

FIG. 19 is a view showing format of IsoRply message.

FIG. 20 is a view showing format of DestIDReq message.

FIG. 21 is a view showing format of DestIDRply message.

FIG. 22 is a view for explaining SDL.

FIG. 23 is a flowchart for explaining processing of status transitionfrom the status of Reset of FIG. 12.

FIG. 24 is a flowchart for explaining processing of status transitionfrom the status of ActPending of FIG. 12.

FIG. 25 is a flowchart for explaining processing of status transitionfrom the status of Act of FIG. 12.

FIG. 26 is a flowchart for explaining processing of status transitionfrom the status of Act of FIG. 12.

FIG. 27 is a flowchart for explaining processing of status transitionfrom any status of FIG. 12.

FIG. 28 is a flowchart for explaining processing of status transitionfrom any status of FIG. 12.

FIG. 29 is a flowchart for explaining processing of status transitionfrom any status of FIG. 13.

FIG. 30 is a flowchart for explaining processing of status transitionfrom the status of Reset of FIG. 13.

FIG. 31 is a flowchart for explaining processing of status transitionfrom the status of ActPending of FIG. 13.

FIG. 32 is a flowchart for explaining processing of status transitionfrom the status of Act of FIG. 13.

FIG. 33 is a flowchart for explaining processing of status transitionfrom the status of Act of FIG. 13.

FIG. 34 is a flowchart for explaining processing of status transitionfrom any status of FIG. 13.

FIG. 35 is a flowchart for explaining processing of status processingfrom any status of FIG. 13.

FIG. 36 is a flowchart for explaining processing of data transfer fromthe status of Act.

FIG. 37 is a flowchart for explaining processing in the case where datais transferred.

FIG. 38 is a flowchart for explaining processing in the case where datais transferred.

FIG. 39 is a flowchart for explaining processing in the case where datais transferred.

FIG. 40 is a flowchart for explaining more detailed processing of stepS287 of FIG. 36.

FIG. 41 is a flowchart for explaining more detailed processing of stepS288 of FIG. 36.

FIG. 42 is a flowchart for explaining more detailed processing of stepS294 of FIG. 36.

FIG. 43 is a flowchart for explaining more detailed processing of stepS300 of FIG. 36.

FIG. 44 is a flowchart for explaining processing in the case where datais received.

FIG. 45 is a flowchart for explaining processing in the case where datais received.

FIG. 46 is a flowchart for explaining processing in the case where datais received.

FIG. 47 is a flowchart for explaining more detailed processing of stepS452 of FIG. 44.

FIG. 48 is a flowchart for explaining more detailed processing of stepS489 of FIG. 44.

FIG. 49 is a flowchart for explaining more detailed processing of stepS479 of FIG. 46.

FIG. 50 is a flowchart for explaining more detailed processing of stepS459 of FIG. 45.

FIG. 51 is a flowchart for explaining more detailed processing of stepS470 of FIG. 45.

FIG. 52 is a flowchart for explaining more detailed processing of stepS483 of FIG. 46.

FIG. 53 is a flowchart for explaining more detailed processing of step462 of FIG. 45.

FIG. 54 is a view showing protocol stack of U plane at the time of useof IP/ATM in the case where ASEL is employed.

FIG. 55 is a view showing protocol stack of C plane at the time of useof IP/ATM in the case where ASEL is employed.

BEST MORE FOR CARRYING OUT THE INVENTION

FIG. 4 shows an example of the configuration of the VOD system to whichthis invention is applied. Similarly to the case shown in FIG. 1, ATM(Asynchronous Transfer Mode) network is used at the backbone side andIEEE 1394 serial bus (IEEE 1394 Standards Draft 8.0v2) is used at thefront end side.

ATM terminal 1 is a server for storing video data. This server 1 isconnected to ATM network 2 through UNI (User-Network Interface) and isadapted to carry out offer of video data, etc. ATM/1394 repeater 3 isconnected to the ATM network 2 through UNI, and is adapted to receivevideo data from the ATM terminal 1 via the ATM network 2 to make anoffer thereof to 1394 terminals 4-1 to 4-7 (When there is no necessityto individually discriminate between 1394 terminals 4-1 to 4-7, theywill be hereinafter referred to as 1394 terminals 4 as occasion maydemand). The ATM/1394 terminals 4 serve to receive video data providedthrough the IEEE 1394 serial bus from the ATM/1394 repeater 3 to displaythem on respective display devices such as CRT or LCD, etc.

Similarly, an ATM/1394 repeater 21 is connected to the ATM network 2through UNI, and serves to receive video data from the ATM terminal 1via the ATM network 2 to make an offer thereof to 1394 terminals 22-1 to22-4 (When there is no necessity to individually discriminate betweenthe 1394 terminals 22-1 to 22-4, they will be hereinafter referred to as1394 terminals 22 as occasion may demand). The 1394 terminals 22 serveto receive video data provided through the IEEE 1394 serial bus from theATM/1394 repeater 21 to display them on respective display devices suchas CRT or LCD, etc.

To the ATM/1394 repeater 21, 1394 terminals 23-1 to 23-4 are alsoconnected through IEEE 1394 serial bus (serial bus of the systemdifferent from that of the IEEE 1394 serial bus to which the 1394terminals 22 are connected). From the ATM terminal 1, video data areprovided (offered) also to these 1394 terminals.

As the connection system of the IEEE 1394 serial bus, both “daisy chain”and “node branch” may be used. In the case of the daisy chain system, asfar as 16 number of 1394 terminals (nodes (equipments having 1394ports)) can be connected, and the maximum length between the terminalsis prescribed by the IEEE 1394 standard requirements so that it iscaused to be 4.5 meters or less. In the case where the node branchsystem is used in combination, 63 number of 1394 terminals can beconnected at the maximum in accordance with the standard requirements.

The limitation of the number of terminals to be connected in accordancewith daisy chain system is based on delay in transmission betweenterminals of the both ends. Moreover, in the IEEE 1394 standard, bus IDNo. is designated by 10 bits of 16 bits for node ID, and Physical ID No.is designated by 6 bits. With respect to one bus, 0 to 62 of Physical IDNos. can be assigned to the 1394 terminals, and the maximum number ofterminals to be connected becomes equal to 63. Since 63 which is thelast physical ID No. is used for broadcast, it cannot be assigned tophysical ID Nos. with respect to individual terminals.

On the other hand, as the bus ID No., values of 0 to 1022 can beassigned to respective buses. Since 1023 which is the last bus ID No. isused for broadcast, it cannot be assigned to bus ID Nos. with respect toindividual buses. Namely, the number of buses can be extended up to 1023at the maximum. Accordingly, 64449 (=1023×63) nodes can be connected atthe maximum within one system.

Each node receives packet sent to the own (self) node ID No. and packetequal in the bus ID No. or sent (addressed) to the Physical ID No. 63which is broadcast.

Moreover, the 1394 terminals are capable of carrying outplug-in/plug-out of the cable of the IEEE 1394 standard in the statewhere power is turned ON, i.e., the equipment is operative. At the timepoint when node is supplemented or deleted, or also at the time whenpower is turned ON, the 1394 terminals automatically carry outreconstruction of the 1394 network to set the node ID numbers for asecond time with respect to respective nodes.

Explanation will now be given in connection with a method of mountingrespective layers for carrying out emulation of AAL (ATM AdaptationLayer)/ATM layer (ITU-TI. 363/ITU-TI.361) on link layers (1394 LINK) ofthe IEEE 1394 standard in devices such as ATM/1394 repeater 3 and 21belonging to the front end side, and 1394 terminals 4, 22, 23, etc.belonging to the front end side. In this example, such layer is calledASEL (ATM over IEEE 1394 Serial bus Emulation layer).

ASEL conceals the IEEE 1394 serial bus and emulates the AAL/ATM layerwith respect to the software of layer (level) which is the same as ASELor higher than that of the corresponding device. For this reason, in thedevice where ASEL is mounted, in the own IEEE 1394 serial bus interface,multi (multiple) separation of VPC (Virtual Pass Connection)/VCC(Virtual Channel Connection) can be made. Further, network accessprotocol software and various application software corresponding to theATM network 2 can be used as they are.

FIG. 5 is a view showing that ASEL entities in the ATM/1394 repeater 3and the 1394 terminals 4-1 to 4-3 are interconnected on the basis of theone-to-one correspondence relationship through respective ASEL-UNIs. Asshown in this figure, when viewed physically, plural ASEL-UNIs can existon a single 1394 serial bus cable.

Moreover, the ASEL entity is divided into operations of the Network side(ATM/1394 repeater 3 side) and User side (1394 terminals 4-1 to 4-3side) with ASEL-UNI being as the boundary. Respective ASEL-UNIs at theNetwork side can be discriminated by allowing 1394 Node Unique IDs thatthe 1394 terminals 4-1 to 4-3 of the User side individually retain(have) and ASEL-UNI IDs assigned to respective ASEL-UNIs to be incorrespondence with each other.

FIG. 6 shows a layer related diagram indicating location of ASEL. Asshown in this figure, the ASEL provides primitives similar to primitivesthat various AALs provide as primitive with respect to Upper layer.Namely, the ASEL receives AAL_UNITDATA.req (request) from the upperlayer to deliver AAL_UNITDATA.ind (indicate). Moreover, the ASELreceives AAL_U_ABORT.req to deliver AAL_U_ABORT.ind. Further, the ASELdelivers AAL_P_ABORT.ind to the upper layer. Thus, software of (theupper layer (e.g., IP layer, IP/ATM layer of FIG. 54 which will bedescribed later and Q.2931 layer, SSCF+SSCOP of FIG. 55 which will bedescribed layer) of ASEL can behave in a manner similar to the casewhere lower layer (e.g., 1394 LINK layer, 1394 PHY layer of FIGS. 54 and55) is AAL.

In this case, AAL_UNITDATA.req and AAL_UNITDATA.ind are primitives forcarrying out data transfer to and from the upper layer.

In the AAL_UNITDATA.req and AAL_UNITDATA.ind primitives, the followinginformation are included.

ID for identifying ASEL_UNI (ASEL-UNI ID)

VPI for identifying Virtual Pass (Virtual Pass Identifier)/VCI foridentifying Virtual Channel (Virtual Channel Identifier) value (VPI/VCIvalue)

AAL5 parameter group (AAL5 parameters): This parameter group is includedin the case where AAL type of ASEL-VCC is AAL5.

Interface Data: In the case where AAL5 is operative in the message mode,this parameter corresponds to complete AAL-SDU (Service Data Unit). Inthe case where AAL5 is operative in the streaming mode, this parametercorresponds to a partial AAL-SDU.

More: This parameter is not used in the message mode. In the streamingmode, this parameter indicates whether or not interface data beingreceived and being transmitted include the last portion of the entiretyof AAL-SDU.

Loss Priority: This parameter indicates Loss Priority of AAL-SDU. Thisparameter is mapped with respect to ASEL-PDU (Protocol Data Unit) headerwhich will be described later.

Congestion Indication: This parameter indicates whether or not AAL-SDUhas experienced the congestion state (status). This parameter is mappedwith respect to ASEL-PDU header which will be described later.

AAL User-User Information: This parameter is transparently transferredby ASEL between ASEL upper layer entities of the same rank (layer). Thisparameter is mapped with respect to ASEL-PDU header which will bedescribed later.

Error Status: This parameter indicates that interface data may includetransmission error. This parameter is used only in the case wheredelivery function of error data is used. This parameter is not includedin AAL_UNITDATA.req primitive.

AAL0 parameter group (AAL0 parameters): This parameter group is includedin the case where AAL type of ASEL-VCC is AAL0.

Interface Data: This parameter corresponds to always complete AAL-SDU.

Loss Priority: This parameter indicates Loss Priority of AAL-SDU. Thisparameter is mapped with respect to ASEL-PDU header which will bedescribed later.

Congestion Indication: This parameter indicates whether or not AAL-SDUhas experienced congestion state (status). This parameter is mapped withrespect to ASEL-PDU header which will be described later.

Error Status: This parameter indicates that interface data may includetransmission error. This parameter is used only in the case wheredelivery function of error data is used. This parameter is not includedin AAL_UNITDATA.req primitive.

Further, AAL_U_ABORT.req, AAL_U_ABORT.ind and AAL_P_ABORT.ind primitivesare primitive for carrying out abort service to and from the upperlayer. These primitives are used only in the case where correspondingASEL-VCC is in the streaming mode of AAL 3/4 or AAL5.

AAL_U_ABORT.req primitive is used by the upper layer of ASEL in order tostart (activate) abort service. AAL_U_ABORT.ind primitive indicates thatthe upper layer of ASEL should abort AAL-SDU partially delivered byindication (instruction) from the upper layer of the same rank (layer)of the opposite (destination) side (ASEL of opposite side).AAL_P_ABORT.ind primitive is used by ASEL entity in order to indicatethat the upper layer of ASEL should abort AAL-SDU partially deliveredresulting from the fact that error takes place at ASEL or the lowerlayer of ASEL.

In AAL_U_ABORT.req, AAL_U_ABORT.ind and AAL_P_ABORT.ind primitives, thefollowing information are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

Moreover, ASEL uses primitive that IEEE 1394 link layer provides as itis as primitive to and from the lower layer. Namely, ASEL deliversLK_ISO_CONT.req to the lower layer to receive LK_CYCLE.ind. Moreover,ASEL delivers LK_ISO.req to the lower layer to receive LK_ISO.ind.Further, ASEL delivers LK_DATA.req to the lower layer to receiveLK_DATA.conf, LK_DATA.ind to deliver LK_DATA.resp to the lower layer.Thus, the 1394 Link layer is not required to become conscious of theupper layer.

LK_ISO_CONT.req primitive is used in making a request for list of(accepted) receive Isochronous channel number in which acceptance ofASEL entity is allowed.

In the LK_ISO_CONT.req primitive, the following information areincluded.

Bus Index for identifying contained 1394 serial bus (1394 Bus Index)

Accepted receive isochronous channel number list

LK_CYCLE.ind primitive is used in order to allow the 1394 Link layer toinform the ASEL entity that Cycle sync event has taken place.

In the LK_CYCLE.ind primitive, the following information are included.

Bus Index for identifying contained 1394 serial bus (1394 Bus Index)

Current cycle count value (Current cycle count): This parameterindicates that current cycle_count value of Cycle_TIME register shouldbe contained (stored).

Current second count value (Current second count): This parameterindicates current value of BUS_TIME register.

LK_ISO.req and LK_ISO.ind primitives are used in order to carry outtransfer of CBR (Constant Bit Rate) data between ASEL and 1394 Linklayer. ASEL entity uses LK_ISO.req primitive in order to request the1394 Link layer for transmission of one Isochronous packet. In addition,the 1394 Link layer uses LK_ISO.ind primitive in order to inform theASEL entity that one Isochronous packet has been received.

In the LK_ISO.req and LK_ISO.ind primitives, the following informationare included.

Bus index for identifying contained 1394 serial bus (1394 Bus Index)

Tag value

Isochronous channel number

Synchronization code: This parameter is not used in the ASEL entity.

Data length

Data: This parameter indicates ASEL-PDU.

Speed: This parameter indicates transmission rate (100M/200M/400M bps)of packet.

Packet status: This parameter indicates result of the receivingoperation of packet executed by 1394 Link layer. This parameter isincluded only in the LK_ISO.ind primitive.

LK_DATA.req primitive is used for carrying out transmission of UBR(Unassigned Bit Rate) or ABR (Available Bit Rate) data. ASEL entity usesthis primitive in order to request the 1394 Link layer for transmissionof single Asynchronous packet.

In the LK_DATA.req primitive, the following information are included.

Bus Index for identifying contained 1394 serial bus (1394 Bus Index)

Destination Self ID

Destination offset: This parameter is fixed to value for indicating thatASEL-PDU is stored in Data field of this Asynchronous packet.

Transaction code: This parameter is fixed to value (i.e.,=1) of “writerequest for data block”.

Extended transaction code: This parameter is not used in the ASELentity.

Retry code: This parameter is fixed to value (i.e.,=1) of “retry notsupported”.

Data length

Data: This parameter indicates ASEL-PDU.

Speed: This parameter indicates transmission rate (100M/200M/400M bps)of packet.

LK_DATA.conf primitive is used by 1394 Link layer in order to allow theupper layer to confirm transmission of one Asynchronous packet.

In the LK_DATA.conf primitive, the following information are included.

Bus Index for identifying contained (accommodated) 1394 serial bus (1394Bus Index)

Request Status: This parameter indicates result of LK_DATA.reqprimitive.

Acknowledge: This parameter includes one of values of Ack_code definedin accordance with the IEEE 1394 standard.

LK_DATA.ind primitive is used for carrying out reception of UBR or ABRdata. The 1394 Link layer uses this primitive in order to inform ASELentity that one Asynchronous packet has been received.

In the LK_DATA.ind primitive, the following information are included.

Bus Index for identifying contained (accommodated) 1394 serial bus (1394Bus Index)

Source Self ID

Destination Self ID

Destination offset: This parameter is fixed to value for indicating thatASEL-PDU is stored in Data field of this Asynchronous packet.

Transaction code: This parameter is fixed to value (i.e.,=1) of “writerequest for data block”

Extended transaction code: This parameter is not used in ASEL entity.

Transaction label: This parameter is not used in ASEL entity.

Retry code: This parameter is fixed to value (i.e.,=1) of “retry notsupported”.

Data length

Data: This parameter indicates ASEL-PDU.

Speed: This parameter indicates transmission rate (100M/200M/400M bps)of packet.

Packet status: This parameter indicates result of receiving operation ofpacket executed by 1394 Link layer.

LK_DATA.resp primitive is used by ASEL entity in order to carry outresponse with respect to received one Asynchronous packet. Namely, bytransmitting one acknowledge packet, that sub action is completed.

In the LK_DATA.resp primitive, the following information are included.

Bus Index for identifying contained (accommodated) 1394 serial bus (1394Bus Index)

Acknowledge: This parameter includes one of values of Ack_code definedin accordance with IEEE 1394 standard.

Bus Occupancy Control: This parameter controls whether or not the 1394Link layer releases govering right of the 1394 serial bus aftertransmission of acknowledge packet.

Speed: This parameter indicates transmission rate (100M/200M/400M bps)of packet.

Further, ASEL carries out transmission/reception of primitives for ASELmanagement including various management information such asconfiguration, fault, performance and alarm, etc. relating to the ASELentity of the opposite (destination) side and the own ASEL entitybetween the ASEL and (local) ASEL layer management entity.

As the primitive for ASEL layer management, seven kinds of primitivesroughly classified are provided. In more practical sense, there areseven kinds primitives of start, reset, connection control, local fault,remote fault, local error and data transfer.

Initially, as primitive relating to starting (Act) of ASEL,MASEL_Act.req from the ASEL layer management is accepted (received) todeliver MASEL_Act.ind. The MASEL_Act.req primitive is used by ASEL layermanagement of User side in order to request that the ASEL entity isshifted to the starting state (Actstatus). The MASEL_Act.ind primitiveis used by ASEL entity in order to inform ASEL layer management that theASEL entity has been shifted to the starting state (Actstatus).

In the MASEL_Act.req and MASEL_Act.ind primitives, the followinginformation are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

Bus Index for identifying contained (accommodated) 1394 serial bus (1394BUS Index): This parameter is not included in the MASEL_ACT.reqprimitive.

As primitive relating to reset of ASEL, MASEL_Reset.req from ASEL layermanagement is accepted (received). The MASEL_Reset.req primitive is usedby ASEL layer management in order to request that ASEL entity shifts tothe reset status (Resetstatus).

In the MASEL_Reset.req primitive, the following information areincluded.

ID for identifying ASEL-UNI (ASEL-UNI ID)

As primitive relating to connection control of ASEL, MASEL_ConSet.reqand MASEL_Con.Rec.req from ASEL layer management are accepted (received)to provide MASEL_ConSet.conf. Moreover, MASEL_ConReI.req from ASEL layermanagement is accepted (received) to provide MASEL_ConReI.conf.

MASEL_ConSet.req primitive is used by ASEL layer management in order torequest that new ASEL-VCC is set.

In MASEL_ConSet.req primitive, the following information are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

ID for uniquely identifying (discriminating between) respective ASELconnections on all ASEL-UNIs existing in the ASEL entity (ASELConnection ID)

AAL Type

Routing Area: This parameter indicates routing area of ASEL-VCC to beset. As value of the parameter, five kinds of parameter values ofExternal/Internal and same 1394 Bus/Internal and other 1394 Bus/Terminate/Unknown can be taken.

Topology: This parameter indicates form of ASEL-VCC. As value ofparameter, two kinds of parameter values of Point-Point/Point-Multipointcan be taken.

AAL5 Specific information: This parameter is used only in the case whereAAL type parameter is AAL5.

Error SDU delivery to Upper Layer

Transmit Maximum SDU Size

Receive Maximum SDU Size

AAL0 Specific information: This parameter is used only in the case whereAAL type parameter is AAL0.

Error SDU delivery to Upper Layer

Transmit Bandwidth

Receive Bandwidth

QoS class: This parameter determines Quality of Service of ASEL-VCC. Asvalue of the parameter, four kinds of parameter values of UBR/CBR/VBR(Variable Bit Rate)/ABR can be taken.

ABR traffic information: This parameter is used only in the case whereQoS class parameter is ABR.

Minimum Transmit Rate

Minimum Receive Rate

Initial Transmit Rate

Initial Receive Rate

Transmit Trm: This parameter is used only at User side.

Transmit Allowed Rate Decrease Time Error: This parameter is used onlyat User side.

Transmit Rate Increase Factor: This parameter is used only at User side.

Transmit Rate Decrease Factor: This parameter is used only at User side.

Transmit Cutoff Decrease Factor: This parameter is used only at Userside.

Transmit Segmentation size: This parameter is equal to dividedrespective transmit ASEL-PDU lengths (sizes). This parameter is not usedin ASEL-VCC of AAL0 type.

Receive Sequence Number: This parameter determines whether or not checkof SN (Sequence Number) field of received ASEL-PDU header should becarried out.

MASEL_ConRec.req primitive is used by ASEL layer management of User sidein order to request recovery (restore) of ASEL-VCC in ASEL-UNI which hasbeen shifted to Reset status resulting from bus reset of 1394 and hasbeen then restored to Act status for a second time.

MASEL_ConSet.conf primitive is used by ASEL entity in order that ASELlayer management confirms result of the operation with respect toMASEL_ConSet.req or MASEL_ConRec.req primitives. In addition, the ASELentity uses MASEL_ConSet.conf primitive in order to inform that theASEL-VCC has been restored.

MASEL_ConRel.req primitive is used for releasing ASEL-VCC by ASEL layermanagement.

MASEL_ConRel.conf primitive is used by ASEL entity in order that theASEL layer management confirms result of the operation with respect tothe MASEL_ConRel.req primitive.

In the MASEL_ConRec.req, MASEL_ConSet.conf, MASEL_ConRel.req andMASEL_ConRel.conf primitives, the following information are included.

ID for idenfitying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

ID for uniquely identifying (discriminating between) respective ASELconnections on all ASEL-UNIs existing in the ASEL entity (ASELConnection ID)

As primitive relating to local fault of ASEL, MASEL_BusHalt.ind andMASEL_ExpireEr.ind are delivered with respect to the ASEL layermanagement. Since these primitives mean that serious (fatal) fault hastaken place in the local ASEL entity, the ASEL layer management entityand the application software should immediately release all resourcesrelating to the ASEL-UNI where fault has taken place.

MASEL_BusHalt.ind primitive indicates at User side that 1394 serial busis stopped and indicates at Network side that 1394 serial bus is stoppedor 1394 terminal of User side is lost.

MASEL_ExpireEr.ind primitive indicates that serious (fatal) errorfollowed by timer expiration has taken place in the local ASEL entity.

In the MASEL_BusHalt.ind and MASEL_ExpireEr.ind primitives, thefollowing information are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

As primitive relating to remote fault of ASEL, MASEL_FatalEr.ind isdelivered with respect to ASEL layer management. Since this primitivemeans that any serious (fatal) error has taken place in the remote ASELentity, the ASEL layer management entity and the application softwareshould immediately release all resources relating to the ASEL-VCC wherefault has taken place.

In MASEL_FatalEr.ind primitive, the following information are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

ID for uniquely identifying (discriminating between) respective ASELconnections on all ASEL-UNIs existing in the ASEL entity (ASELConnection ID)

Error Code: This parameter is a parameter obtained by coding the faultcontent which has taken place in the remote ASEL entity.

As primitive relating to local error of ASEL, MASEL_IsoEr.ind,MASEL_DestEr.ind and MASEL_StsEr.ind are delivered with respect to theASEL layer management.

Since the MASEL_IsoEr.ind and MASEL_DestEr.ind primitives mean thaterror relating to ASEL-VCC setting has taken place in the local ASELentity, the ASEL layer management entity and the application softwareshould quickly release all resources relating to the ASEL-VCC wherefault has taken place.

In MASEL_IsoEr.ind and MASEL_DestEr.ind primitives, the followinginformation are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

ID for uniquely identifying (discriminating between) respective ASELconnections on all ASEL-UNIs existing in the ASEL entity (ASELConnection ID)

MASEL_StsEr.ind primitive indicates that error relating to statustransition has taken place in the local ASEL entity.

In the MASEL_StsEr.ind primitive, the following information areincluded.

ID for identifying ASEL-UNI (ASEL-UNI ID)

As primitive for carrying out data transfer including layer managementinformation of ASEL, MASEL_DATA.req is accepted (received) from ASELlayer management to deliver MASEL_DATA.ind. These primitives are usedfor transferring arbitrary management information between ASEL layermanagement entities of the same rank (layer) of the opposite(destination) side.

Parameters in the MASEL_DATA.req and MASEL_DATA.ind primitives includeparameters having the same content as AAL0 parameters in theAAL_UNITDATA.req and AAL_UNITDATA.ind primitives. This is because AALtype of ASEL-PDU for transferring these primitives uses AAL0 at alltimes.

In the MASEL_DATA.req and MASEL_DATA.ind primitives, the followinginformation are included.

ID for identifying ASEL-UNI (ASEL-UNI ID)

VPI/VCI value

Management ID: This parameter is used in order to identify kind ofmanagement information included as interface data.

Interface Data: This parameter always corresponds to complete AAL-SDU.

Loss Priority: This parameter indicates Loss Priority of AAL-SDU. Thisparameter is mapped with respect to ASEL-PDU header which will bedescribed later.

Congestion Indication: This parameter indicates whether or not AAL-SDUhas experienced the congestion state (status). This parameter is mappedwith respect to ASEL-PDU header which will be described later.

Error Status: This parameter indicates that interface data may includetransmission error. This parameter is used only in the case wheredelivery function of error data is used. This parameter is not includedin the MASEL_DATA.req primitive.

The main functions of ASEL will now be described. First of all, VPC/VCCmulti (multiple) separation in respective ASEL-UNIs can be made. Namely,ASEL entity permits plural VPC/VCC to be set on Isochronous channel. Itis to be noted that VPI (Virtual Path Identification)/VCI (VirtualChannel Identification) values of VPC/VCC set on different Isochronouschannels may overlap with each other.

Moreover, the ASEL entity permits setting of plural VPI/VCI values anddiscrimination therebetween every Dest (Destination)-ID which is node IDNo. of the destination (opposite side) at the time of transmission andevery Src (Source)-ID which is the own (source) node ID No. at the timeof reception.

It is to be noted that VPI/VCI values of VPC/VCC in different Dest-ID orSrc-ID may overlap with each other. Various parameters relating toVPC/VCC are set by using MASEL_ConSet.req primitive from ASEL layermanagement.

Secondly, ASEL guarantees QoS (Quality of Service). Namely, ASEL carriesout CBR (Constant Bit Rate) service of ATM by using the Isochronouspacket of the IEEE 1394 standard, and carries out UBR (Unassigned BitRate) service and ABR (Available Bit Rate) service of ATM by using theAsynchronous packet of the IEEE 1394 standard to guarantee QoS withrespect to ASEL user.

FIG. 7 shows data format of packet caused to undergotransmission/reception in the IEEE 1394 standard. This packet consistsof header portion and data field. In the header portion, in the case ofAsynchronous packet, information such as destination address, sourcenode-address and transfer data-size, etc. are stored; in the case of theIsochronous packet, information such as channel ID, etc. is stored. Datato be actually caused to undergo transmission (transmitted) are storedin quadlet units (4 byte units) in the data field. The size of the datafield is adjustable. In the data field, zero pad bytes are suitablyinserted as occasion demands into the last portion of data so that sizeof the packet becomes 4 byte units.

In the case where the transmission rate (speed) is 100 Mbps (megabits/sec), the maximum length (size) of the packet becomes equal to 1024bytes in the case of the Isochronous packet of the IEEE 1394 standard,and becomes equal to 512 bytes in the case of the Asynchronous packet ofthe IEEE 1394 standard. In addition, prior to carrying out datatransfer, transmit segment size parameters of MASEL_ConSet.req primitiveare set every respective ASEL-VCCs in the ASEL entity. Thus, withrespect to packets which exceed any one of these values, those packetsare transmitted in the state divided into plural packets.

For example, in the case of the Asynchronous packet of the IEEE 1394standard, packet transmitted from a predetermined node is transferred toall nodes within the IEEE 1394 serial bus. Accordingly, respective nodesread the header portion of this packet to read it thereinto when data ofthis packet is packet data addressed to the own node. Moreover, in thecase of the Isochronous packet of the IEEE 1394 standard, channel ID isused without using node-address. For example, in the case where data aresimultaneously transferred from plural nodes, channel IDs foridentifying (discriminating between) their contents are respectively setat data to be transferred. Thus, the node which receives data setschannel ID corresponding to predetermined transfer data to accept(receive) only desired data. Accordingly, two nodes or more can alsoaccept (receive) data of the same channel ID. In this way, data can betransferred from a predetermined node to any other predetermined node.

Moreover, as has been shown in FIG. 7, ASEL-PDU (Protocol Data Unit) isinserted into data field of Write request for data block packet orIsochronous data-block packet format of Asynchronous packet formats withdata block payload prescribed in the IEEE 1394 standard. As describedlater with reference to FIGS. 8 to 10, ASEL-PDU consists of headerportion and payload portion.

In the case of transferring ASEL-PDU, values of the fields describedbelow are fixed in the header of the Asynchronous packet (Write requestfor data block packet).

Destination offset field: The field value is set to specific offsetvalue for indicating that ASEL-PDU is stored in the data field of thisAsynchronous packet.

Transaction code field: 0001: write request for data block

Extended transaction code field: 0000

In the case of transferring ASEL-PDU, values of the fields describedbelow are fixed in the header of the Isochronous packet (Isochronousdata-block packet).

Transaction code field: 1010: Isochronous data block

As shown in FIGS. 8 to 10, the ASEL-PDU consists of header portion andpayload portion.

In the ASEL-PDU header, the following information are included.

VPI/VCI information for identifying VPC/VCC

ASEL layer management discrimination information

QoS class

AAL-SDU (Service Data Unit) last (final) indication

AAL-SDU sequence No.

AAL type discrimination information

AAL specific information

Moreover, ASEL-PDU payload includes information as described below.

AAL-SDU

ASEL realizes the above-described various functions by using ASEL-PDU asshown in FIG. 8 between ASEL entities of the same rank (layer). FIG. 8shows format of ASEL-PDU common to all AAL types.

In this figure, VPI/VCI value is VPI/VCI value field, and 1 byte isassigned to VPI value and 2 bytes are assigned to VCI value. Thispermits emulation of VPI and VCI in ATM. MI is Management informationIndicator field consisting of 1 bit, and indicates whether or not thecontent of AAL-SDU is ASEL layer management information. When thatcontent is not ASEL layer management information, value 0 is set, whilethat content is ASEL layer management information, value 1 is set.

MNG-ID is ASEL Layer Management Identifier field of 3 bits. When thisfield is Peer ASEL Entity management, value 000 is set, and when thisfield is Segment F5 flow OAM, value 001 is set. When this field isEnd-End F5 flow OAM, value 010 is set. Further, when this field isResource management, value 011 is set. Other values are reserved. It ishere noted that “reserved” means undefined state.

QoS Class is QoS Class field of 4 bits. When URB service is used, value0000 is set. When CBR service is used, value 0001 is set. Moreover, inthe case where VBR (Variable Bit Rate) service is used, value 0010 isset. Further, in the case where ABR (Available Bit Rate) service isused, value 0011 is set. Other values are reserved.

MR is More Indication field of 1 bit, and indicates whether or not PDUcaused to undergo transmission/reception includes the terminatingportion of AAL-SDU. When the terminating portion of AAL-SDU is included,value 0 is set. When the terminating portion of AAL-SDU is not included,value 1 is set.

SN is Sequence Number field of 7 bits, and is caused to undergomanagement every VPI/VCI value. Every time ASEL-PDU in which the contentof AAL-SDU is information except for ASEL layer management informationis transmitted, 1 is added by modulo 128. In the case where the contentof AAL-SDU includes ASEL layer management information, this field is notadded. Accordingly, in the case where values of the SN field arediscontinuous, the receiving side can detect that losing (missing) orerroneous insertion of ASEL-PDU has taken place resulting fromtransmission error, etc. on the way.

AAL-Type field is constituted with 4 bits and indicates type of AAL.When type of AAL is AAL0 (is equal to null AAL or raw cell), i.e., thereis no AAL, value 0000 is set. When type of AAL is AAL 1, value 0001 isset. When type of AAL is AAL 2, value 0010 is set. When type of AAL isAAL 3 or 4, value 0011 is set. When type of AAL is AAL5, value 0101 isset. In addition, value 0100 and other values are reserved.

AAL Specific Information field consists of 20 bits, and specificinformation are stored every respective AAL types. Payload (AAL-SDU)field has variable length, and stores SDU caused to undergotransmission/reception to and from the upper layer or the layermanagement. PAD field is zero pad bytes within data field ofAsynchronous/Isochronous packet of the IEEE 1394 standard, and Payloadfield is inserted so that there results multiple of integer of 4 bytes.

FIG. 9 shows format and coding example of ASEL-PDU (AAL5 Type). In theASEL-PDU of AAL5 Type, value 0 is set in MI field shown in FIG. 8 andvalue 0101 is set in AAL Type field. Further, information peculiar toAAL5 Type is stored in AAL Specific Information field. Namely, LP isLoss Priority field of 1 bit, and value 0 is set at the time of low losspriority and value 1 is set at the time of high loss priority. LP fieldis used when preferentially undergoing aborting (disposal) from cellswhich are not important in the case where there results Congestion statewithin the system. For example, a processing is conducted such thatcells where value 0 is set are difficult to undergo aborting (disposal),and cells where value 1 is set are easy to undergo aborting (disposal).

CI is Congestion Indicator field of 1 bit. When there is no Congestionpast record, value 0 is set. When there is Congestion past record, value1 is set. 2 bits subsequent thereto are reserved.

EI is Error Indicator field of 1 bit. When there is no error, value 0 isset. When error exists, value 1 is set. ER-ID is Error Identifier fieldof 7 bits. In the case of non-use, value 0000000 is set. Value 0000001to Value 0111111 are reserved. In the case of CPCS (Common PartConvergence Sublayer) CRC error, value 1000001 is set. In the case ofCPCS-SDU Length error, value 1000010 is set. Other values are reserved.

The next CPCS-UU is CPCS-User to User information field of 8 bits.

FIG. 10 shows format and coding example of ASEL-PDU (AAL0 Type). In theformat of ASEL-PDU of AAL0 type, value 0 is set with respect to MR fieldshown in FIG. 8 and value 0000 is set with respect to AAL Type field.Further, information peculiar to AAL0 Type is stored into AAL SpecificInformation field. Namely, LP is Loss Priority field of 1 bit. In thecase of low loss priority, value 0 is set. In the case of high losspriority, value 1 is set. CI is Congestion Indicator field of 1 bit.When no congestion past record exists, value 0 is set. When congestionpast record exists, value 1 is set. 2 bits subsequent thereto arereserved.

EI is Error Indicator field of 1 bit. When there is no error, value 0 isset. When there is error, value 1 is set. ER-ID is Error Identifierfield of 7 bits. In the case where this field is not used, value 0000000is set. At the time of OAM (Operation And Maintenance) cell EDC (ErrorDetection Code) error, value 0000001 is set. Other values are reserved.The next (subsequent) 8 bits are reserved.

The specification of the ASEL connection management which is one offunctions of ASEL will now be indicated.

As shown in FIG. 11, respective one ASEL-CMIs (Connection ManagementInterfaces) exist on ASEL-UNIs. The ASEL-CMI is interface forinterconnecting ASEL-CMEs (Connection Management Entities) mounted inATM/1394 repeater 3 which is the Network side and 1394 terminals 4-1 to4-3 which are User Side.

The functions of ASEL-CMI are indicated below.

ASEL-PDUs called “ASEL Connection Management Protocol (ASEL-CMP)” aretransferred through ASEL-CMI.

ASEL-CMP transfers message between ASEL-CMEs of the same rank (layer) byASEL-PDUs using 1394 Asynchronous packet of the AAL0 type to controlASEL-VCC.

Coding of respective fields of ASEL-PDU header used in the message ofASEL-CMP is as follows:

VPI/VCI valuye=all “0”

MI=1

MNG-ID=000 (Same Rank (Layer) ASEL Entity Management)

QoS class=0000

ALL-Type =AAL0

List of messages used in ASEL-CMP is shown in Table 1 and Table 2. Themessage of the Table 1 are messages in which there is possibility thatASEL-CME may be caused to undergo status transition when that messagetransmitted or received. The messages of the Table 2 are messages inwhich no state transition takes place.

TABLE 1 Message of ASEL-CMP where status transition takes placeConnection Name Direction Form Parameter WakeUp U→N Broadcast User sideSelf ID, User side Node Unique ID ActReq N→U One-to-One User side SelfID, User side Node Unique ID, Network side Self ID, Network side NodeUnique ID ActAck U→N One-to-One Error Code

TABLE 2 Message of ASEL-CMP where no status transition takes placeConnection Name Direction Form Parameter IsoReq U→N One-to-One AssignedVPI/VCI IsoRply N→U One-to-One Assigned VPI/VCI, Assigned IsochronousChannel Value, ASEL- VCC Operation Speed DestIDReq U→N One-to-OneAssigned VPI/VCI DestIDRply N→U One-to-One Assigned VPI/VCI, DestinationSelf ID, ASEL-VCC Operation Speed

WakeUp message (its format will be described later with reference toFIG. 15) is used when respective ASEL-CMEs of User side inform Networkside that their own starting operations have been completed. Thismessage always uses broadcast address as Destination ID of 1394Asynchronous packet.

ActReq message (its format will be described later with reference toFIG. 16) is used when after WakeUp message is received, ASEL-CME ofNetwork side requests respective User sides for starting of ASEL-CMEs,and requests registration of Self ID (e.g., at the time of power ON,etc., ID automatically added by the IEEE 1394 standard) and Node UniqueID of Network side.

ActAck message (its format will be described later with reference toFIG. 17) is used when ASEL-CME of User side informs Network side ofresult of the operation with respect to ActReq reception.

IsoReq message (its format will be described later with reference toFIG. 18) is used when ASEL-CME of User side requests Network side forvalue of Isochronous channel which solves assigned VPI/VCI.

IsoRply message (its format will be described later with reference toFIG. 19) is used when ASEL-CME of Network side responds to IsoReq inorder to assign Isochronous channel to User side.

DestIDReq message (its format will be described later with reference toFIG. 20) is used when ASEL-CME of User side requests Network side forvalue of Destination ID of Asynchronous packet which solves assignedVPI/VCI.

DestIDRply message (its format will be described later with reference toFIG. 21) is used when ASEL-CME of Network side responds to DestIDReq inorder to teach Self ID of destination node to User side.

Status transitions in ASEL-CMEs of User side and Network side arerespectively shown in FIGS. 12 and 13.

Status transitions independently take place every respective ASEL-CMIs.For this reason, the device in which plural ASEL-CMIs exist is requiredto carry out management of the statuses every corresponding respectiveASEL-CMEs.

In FIGS. 12 and 13, Reset Status indicates whether or not tree topologyis established immediately after initialization state or reset of 1394serial bus; ActPending Status indicates the statuses (states) waitingfor ActReq message reception from Network side at User side (FIG. 12)and ActAck message reception from User side at Network side (FIG. 13);and Act Status indicates the status where Network side and User sideboth recognize to each other that ASEL-CMEs are activated.

Only in the Act Status, ASEL-CMEs of Network side and User side cancarry out transmission/reception of message for acquiring resourcesshown in the Table 2 (i.e., IsoReq, IsoRply, DestIDReq, DestIDRply).

Further, Timer_Reset indicates bus reset allowed time period of 1394serial bus. Ordinarily, even in the case where 1394 bus reset takesplace, 1394 bus is restored from the reset status for (within) several100 μs. ASEL-VCC must not be released by such momentary transition tothe reset status. Namely, until Timer_Reset is expired, respectiveASEL-CMEs of Network side and User side must maintain all settings ofASEL-VCC. However, until respective ASEL-CMEs are restored to ActStatus, Asynchronous packets in ASEL-VCCs of topology type ofPoint-Point will be caused to undergo disposal (aborting). This isbecause DestinationIDs in these Asynchronous Packets are uncertained atthis time point.

In addition, Timer-ActPending indicates timing for re-sending(re-transmitting) Wake up message at User side or ActReq message atNetwork side.

FIG. 14 shows format of field common to all ASEL-CMP messages.

In FIG. 14, Message ID field consists of 8 bits and indicates kind ofASEL-CMP messages. Value 00000000 is not yet used. In the case of theWake up message, value 00000001 is set. In the case of ActReq message,value 00000010 is set. In the case of ActAck, value 00000011 is set. Inthe case of IsoReq message, value 00000100 is set. In the case ofIsoRply message, value 00000101 is set. In the case of DestIDReqmessage, value 00000110 is set. In the case of DestIDRply message, value00000111 is set. In addition, other values are reserved.

Reference ID field consists of 16 bits, and indicates ID Nos. thatNetwork side and User side make reference to each other in order thatcontradiction of the status transition does not take place therebetween.In the case where ASEL-CME of User side transmits Wake up message incarrying out transition from Reset Status, ASEL-CME of User side mustassign new Reference ID of unique value to that Wake up message in thatASEL-CMI. ASEL-CMEs of User side and Network side must use this value ascurrent Reference ID. Further, in the case where an arbitrary messageexcept for Wake up message having value different from value of currentReference ID is received, that message must be disregarded.

Error Code field consists of 8 bits, and indicates factor of error oralarm which has taken place in ASEL-CME. Error Code fields are definedevery respective messages. The detail of coding rule will be describedlater. In the case where error and alarm do not exist, value 00000000 isset. In the case where event to be alarmed takes place, value 10 is setat the high order 2 bits. In the case where message with alarm isreceived, processing is continued as far as possible. In the case whereevent subject to serious (fatal) error takes place, value 11 is set atthe high order 2 bits. In the case where message with error is received,ASEL layer management is immediately informed of error. Other values arereserved.

Format of Wake up message is shown in FIG. 15.

In FIG. 15, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of alarm ofre-sending (retransmission) of message, value 10000001 is set. Othervalues are reserved.

User side Node_Unique_ID (NU_ID) field consists of 64 bits, and globaland unique value of Node Unique ID that 1394 terminal of User sideretains (has) is set by ASEL-CME of User side. The high order 24 bitsindicate Vendor_ID and the low order 40 bits indicate Chip_ID.

User side Self ID field consists of 16 bits, and value of Self ID whichis node address of User side is set by ASEL-CME of User side. The highorder 10 bits indicate BUS_ID and the low order 6 bits indicate PHY_ID.

Format of ActReq message is shown in FIG. 16.

In FIG. 16, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of alarm ofre-sending (retransmission) of message, value 10000001 is set. Further,in the case of alarm of topology change, value 10000010 is set. Othervalues are reserved.

Network side Node_Unique_ID (NU_ID) field consists of 64 bits, and oneof global and unique values of Node Unique ID that device of Networkside retains (has) every 1394 serial bus is set by ASEL-CME of Userside. The high order 24 bits indicate Vendor_ID and the low order 40bits indicate Chip_ID.

Network side self ID field consists of 16 bits, and value of Self IDwhich is node address of Network side is set by ASEL-CME of Networkside. The high order 10 bits indicate BUS_ID and the low order 6 bitsindicate PHY_ID.

Format of ActAck message is shown in FIG. 17.

FIG. 17, with respect to coding of Error Code field, in the case wherethere is no error, value 00000000 is set. In the case of serious (fatal)error of failure in starting, value 11000001 is set. Other values arereserved.

Format of IsoReq message is shown in FIG. 18.

In FIG. 18, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of alarm ofre-sending (retransmission) of message, value 10000001 is set.

Assigned VPI/VCI field consists of 24 bits, and VPI value (8 bits) andVCI value (16 bits) assigned by MASEL-ConSet.req primitive from the ownASEL layer management are set.

Format of IsoRply message is shown in FIG. 19.

In FIG. 19, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of serious(fatal) error where no available Isochronous channel exists, value11000010 is set.

Assigned VPI/VCI field consists of 24 bits, and VPI value (8 bits) andVCI value (16 bits) included in IsoReq message from User side are set.

Assign Isochronous Channel field consists of 8 bits, and Tag field of1394 Isochronous packet header is set at the high order 2 bits.Isochronous channel that the Network side has assigned is set at the loworder 6 bits.

As an example of how to use Tag field, this field is used as bit-map forfiltering at the time of reception of Isochronous packet. For example,an approach is employed to allow the high order bit of 2 bits to beListen Bit of Network Side and to allow the low order bit thereof to beListen Bit of User Side to accept packet only in the case wherecorresponding bit indicates “1”. This way of use is effective in thecase there is a necessity such that when filtering function by theIsochronous channel is not sufficient (e.g., the number of channelswhich can be set is small, etc.), respective nodes prevent reception ofunnecessary packets as simple as possible. For example, Tag field ofDummy packet transmitted when there is no packet to be sent is set to(0, 0), thereby making it possible to disregard reception of unnecessarypacket without discriminating value of Isochronous channel. In addition,(0, 1) is assigned to ASEL-VCC that only User side should receive, (1,0) is assigned to ASEL-VCC that only Network Side should receive, and(1, 1) is assigned to ASEL-VCC that User Side and Network side shouldboth receive.

Moreover, with respect to Tag field, there may be also employed a way ofuse to extend the number of channels of Isochronous channel. Namely,Isochronous channel of 6 bits is extended to 8 bits to use the highorder 2 bits thereof as Tag field. At this time, value 00 of Tag fieldis not used. Thus, as the entirety of field, values from the value00000000 up to the value 00111111 result in values which cannot beutilized. As a result, values from the value 01000000 up to the value11111111 are set as available (utilizable) Isochronous channel.

ASEL-VCC Opr_Speed field consists of 8 bits, and indicates datatransferrable speed in this ASEL-VCC. In the case of S100 (100 Mbps),value 00000000 is set. In the case of S200 (200 Mbps), value 00000001 isset. Further, in the case of S400 (400 Mbps), value 00000010 is set.Other values are reserved.

Format of DestIDReq message is shown in FIG. 20.

In FIG. 20, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of alarm ofre-sending (retransmission) of message, value 10000001 is set.

Assigned VPI/VCI field consists of 24 bits, and VPI value (8 bits) andVCI value (16 bits) assigned by MASEL_ConSet.req primitive from the ownASEL layer management are set.

Format of DestIDRply message is shown in FIG. 21.

In FIG. 21, with respect to coding of Error Code field, in the casewhere there is no error, value 00000000 is set. In the case of serious(fatal) error such that Destination ID cannot be found, value 11000011is set.

Assigned VPI/VCI field consists of 24 bits, and VPI value (8 bits) andVCI value (16 bits) included in DestIDReq message from User side areset.

Destination Self ID field consists of 16 bits, and value of Self IDwhich is node address of the destination corresponding to this ASEL-VCCis set. The high order 10 bits indicate BUS_ID and the low order 6 bitsindicate PHY_ID.

ASEL-VCC Opr_Speed field consists of 8 bits, and indicates datatransferrable speed in this ASEL-VCC. In the case of S100 (100 Mbps),value 00000000 is set. In the case of S200 (200 Mbps), value 00000001 isset. Further, in the case of S400 (400 Mbps), value 00000010 is set.Other values are reserved.

Explanation will now be given in connection with the process of thestatus transition of ASEL-CME by using the flowchart represented by SDL(Stateand Description Language). In this case, the list of SDL keys isshown in FIG. 22. Respective symbols shown in the flowcharts of FIGS. 23to 25 have meanings as shown in FIG. 22. The process relating tocommands of ASEL-CME at User side shown in FIG. 12 is shown in FIGS. 23to 28, and the process relating to commands of ASEL-CME at Network sideshown in FIG. 13 is shown in FIGS. 29 to 35. Further, data transferprocess of the transmitting side is shown in FIGS. 36 to 43, and datatransfer process of the receiving side is shown in FIGS. 44 to 53.

These processes will now be described. Prior thereto, parametersindicated in the respective processes will be explained as below.

The following parameters are set in a manner common to ASEL entities.

aselLayerOprMode indicates whether ASEL entity is operative in the modeof User side or in the mode of Network side, and can take three kinds ofvalues of Unknown (0), User side (1) and Network side (2).

aselLayerTimer_Reset indicates time (time period) from Timer_Reset startup to expiration, and is represented by integer value ranging from 1 to64. Unit is second. Default value is 32.

aselLayerTimer_ActPending indicates time (time period) fromTimer_ActPending start up to expiration, and is represented by integervalue ranging from 1 to 64. Unit is second. Default value is 1.

aselLayerMaxTimerExpire indicates maximum value of the allowable numberof expirations of Timer_Act Pending timer, and can take value rangingfrom 1 to 255. Default value is 4.

aselLayer1394DestOffset indicates special Destination Offset addressused for discriminating that the content (payload) of Asynchronous writerequest packet being received is ASEL-PDU, and can take integer valuesof 48 bits (0 to 0xffffffffffff).

The following parameters are set independently every ASEL-UNIs.

aselLayerUniId indicates value for uniquely identifying ASEL-UNI(ASEL-UNI ID value).

aselLayer1394BusIndex indicates value for uniquely identifying(discriminating) 1394 serial bus existing on the ASEL-UNI (1394 BusIndex value).

aselLayerStatus indicates current operating Status of ASEL-UNI, and cantake three kinds of values of Reset (0), ActPending (1) and Act (2)similarly to Status of ASEL-CME. Initial value is Reset (0).

aselLayerNetSideNodeUniqId globally indicates unique value foridentifying 1394 node of Network side of ASEL-UNI (Network SideNode_Unique_ID value), and can take integer values of 64 bits (0 to0xffff ffff ffff ffff).

aselLayerUserSideNodeUniqId globally indicates unique value foridentifying 1394 node of User side of ASEL-UNI (User side Node_Unique_IDvalue), and can take integer values of 64 bits (0 to 0xffff ffff ffffffff).

aselLayerNetSideNodeSelfId indicates physical address value on 1394serial bus for identifying 1394 node of Network side of ASEL-UNI(network side SelfID), and can take integer values of 16 bits (0 to0xffff). The initial value and the value after clear are assumed to be0xffff.

aselLayerUserSideNodeSelfId indicates physical address value on the 1394serial bus for identifying 1394 node of User side of ASEL-UNI (User sideSelfID), and can take integer values of 16 bits (0 to 0xffff). Theinitial value and the value after clear are assumed to be 0xffff.

The following parameters are set independently every ASEL-VCCs.

aselVccVpi indicates VPI value of ASEL-VCC, and can take value rangingfrom 0 to 255.

aselVccVci indicates VCI value of ASEL-VCC, and can take value rangingfrom 0 to 65535.

aselVccConnId indicates value for uniquely identifying ASEL-VCC throughall ASEL-UNIs (ASEL Connection ID value).

aselVccRouteArea indicates the range of routing of ASEL-VCC, and cantake five kinds of values of External (1), Internal and same 1394 bus(2), Internal and other 1394 bus (3), Terminate (4) and Unknown (5).External (1) routing indicates that calling party or called party doesnot exist on all ASEL-UNIs.

aselVccTopology indicates type of topology of set ASEL-VCC, and can taketwo kinds of values of Point-Point (1) and Point-Multipoint (2).

aselVccStatus indicates status of ASEL-VCC, and can take two kinds ofvalues of Down (0) and Up (1). The upper layer of ASEL can carry outdata transfer only when this status is Up (1).

aselVccAalType indicates AAL type that ASEL-VCC uses, and can take fivekinds of values of AAL0(0), AAL1(1), AAL3/4(3) and AAL5(5). In the casewhere ASEL-VCC does not use AAL, AAL(0) is set.

aselVccQosType indicates bidirectional QoSclass of transmission andreception of ASEL-VCC, and can take four kinds of values of UBR(0),CBR(1), VBR(2) and ABR(3).

aselVccOprSpeed indicates data transferrable speed of ASEL-VCC, and cantake three kinds of values of S100(0), S200(1) and S400(2).

aselVccTransmitSegLen is used in dividing long AAL-SDU into several dataunits of the same length except for the last data unit. Those data unitsare transmitted as ASEL-SDU. Value of this parameter is equal to eachASEL_PDU length to be transmitted, and is indicated by integer value ofbyte unit.

aselVccReceiveSeqUse sets, every ASEL-VCC, whether or not ASEL entityuses Sequence Number of received ASEL header, and can take two kinds ofvalues of No use (0) and Use (1).

aselVccIsoChannel indicates Tag value and Isochronous channel value thatASEL-VCC uses, and is represented by integer value ranging from 0 to255.

aselVccIsoDelayVariationTolerance indicates allowed value of delayfluctuation with respect to ASEL-PDU in ASEL-VCC on Isochronous link,and is represented by No. of ASEL-PDUs per unit time.

aselVccIsoTransmitBand indicates transmit band of ASEL-PDU in ASEL-VCCon Isochronous link, and unit is represented by 64 Kbps (1 Byte/Cycle).

aselVccIsoReceiveBand indicates receive band of ASEL-PDU in ASEL-VCC onIsochronous link, and unit is represented by 64 Kbps (1 Byte/Cycle).

aselVccAsyncDestId indicates Destination ID used at the time oftransmission of ASEL-PDU at ASEL-VCC on Asynchronous link.

aselVccAsyncPeakTransmitRate indicates peak transmit rate of ASEL-PDU inASEL-VCC on Asynchronous link, and unit is represented by 64 Kbps. Thisparameter can limit sum total of ASEL-PDU lengths per unit time.

aselVccAsyncPeakReceiveRate indicates peak receive rate of ASEL-PDU inASEL-VCC on Asynchronous link, and unit is represented by 64 Kbps.

The following parameters are independently set every AAL on ASEL-VCC.

aselAalConnVpi indicates VPI value of ASEL-VCC which is using AAL.

aselAalConnVci indicates VCI value of ASEL-VCC which is using AAL.

aselAal5ConnErSduDeliver is related to only ASEL-VCC which is usingAAL5. In the case where CRC error is found out in received AAL5-SDU,whether or not corresponding SDU is delivered to the upper layer can beselected as emulation function of AAL5 in ASEL entity.

aselAal5ConnTransmitMaxSduSize indicates the maximum AAL5-SDU size (unitis octet) supported in the transmit direction of ASEL-VCC, and can takevalue ranging from 0 to 65535. Default value is 9188.

aselAal5ConnReceiveMaxSduSize indicates the maximum AAL5-SDU size (unitis octet) supported in the receive direction of ASEL-VCC, and can takevalue ranging from 0 to 65535. Default value is 9188.

aselAal0ConnErSduDeliver is related to only ASEL-VCC which is usingAAL0. In the case where CRC error is found out in received AAL0-SDU,whether or not corresponding SDU is delivered to the upper layer can beselected as emulation function of AAL0 in ASEL entity.

The following parameters are independently set every ASEL-VCC in whichQoS Class is ABR.

aselVccAbrVpi indicates VPI value of ABR ASEL-VCC.

aselVccAbrVci indicates VCI value of ABR ASEL-VCC

aselVccAbrMinTransmitRate indicates the minimum transmit rate ofASEL-PDU in ABR ASEL-VCC, and unit is represented by 64 Kbps.

aselVccAbrMinReceiveRate indicates the minimum receive rate of ASEL-PDUin ABR ASEL-VCC and unit is represented by 64 Kbps.

aselVccAbrInitialTransmitRate indicates initial transmit rate ofASEL-PDU in ABR ASEL-VCC and unit is represented by 64 Kbps. Thisparameter derives sum total of the first ASEL-PDU lengths per unit timewhere occurrence of data starts. Value of this parameter must not begreater than aselVccAsyncPealTransmitRate and is ordinarily smaller thanthat value.

aselVccAbrInitialReceiveRate indicates initial receive rate of ASEL-PDUin ABR ASEL-VCC and unit is represented by 64 Kbps.

aselVccAbrAllowedTransmitRate indicates transmittable rate of ASEL-PDUin ABR ASEL-VCC and unit is represented by 64 Kbps. This parameter canlimit sum total of ASEL-PDU lengths per unit time. Value of thisparameter must not be greater than aselVccAsyncPeakTransmitRate and isordinarily smaller than that value.

aselVccAbrAllowedReceiveRate indicates receivable rate of ASEL-PDU inABR ASEL-VCC and unit is represented by 64 Kbps.

aselVccAbrTransmitTrm indicates, by mili second, upper limit of transmitRM cell interval included in ASEL_PDU in active generation source, andcan take eight kinds of values of trm0point78125(1), trmipoint5625(2),trm3point125(3), trm6point25(4), trm12point5(5), trm25(6), trm50(7),trm100(8). Default value is trm100(8).

aselVccAbrTransmitCdf is cut off decrease factor, and make a control soas to decrease rate in a manner related to missing or delay of RM cellin the opposite direction included in ASEL-PDU. This parameter can takeeight kinds of values of cdfo(1), cdfOneOver64(2), cdfOneOver32(3),cdfOneOver16(4), cdfOneOver8(5), cdfOneOver4(6), cdfOneOver2(7),cdfOne(8). According as this value is caused to be greater value, therate is resultantly decreased in a short time. Default value iscdfOneOver16(4).

aselVccAbrTransmitRif is rate increase factor, and makes a control so asto increase rate in the case where RM cell in the opposite directionincluded in ASEL-PDU is received along with CI=0 and NI=0. Thisparameter can take 16 kinds of values of rifOneOver32768(1),rifOneOver16384(2), rifOneOver8192(3), rifOneOver4096(4),rifOneOver2048(5), rifOneOver1024(6), rifOneOver512(7),rifOneOver256(8), rifOneOver128(9), rifOneOver64(10), rifOneOver32(11),rifOneOver16(12), rifOneOver8(13), rifOneOver4(14), rifOneOver2(15),rifOne (16). According as this value is caused to be greater value, therate is resultantly increased in a short time. Default value isrifOneOver16(12).

aselVccAbrTransmitRdf is rate decrease factor, and makes a control so asto decrease rate in the case where RM cell in the opposite directionincluded in ASEL-PDU is received along with CI=1. This parameter cantake 16 kinds of values of rdfOneOver32768(1), rdfOneOver16384(2),rdfOneOver8192(3), rdfOneOver4096(4), rdfOneOver2048(5),rdfOneOver1024(6), rdfOneOver512(7), rdfOneOver256(8), rdfOneOver128(9),rdfOneOver64(10), rdfOneOver32(11), rdfOneOver16(12), rdfOneOver8(13),rdfOneOver4(14), rdfOneOver2(15), rdfOne(16). According as this value iscaused to be greater value, the rate is resultantly decreased in a shorttime. Default value is rdfOneOver16(12).

aselVccAbrTransmitAdtf is ACR decrease time factor and indicates allowedtime of interval for transmitting RM cells included in ASEL-PDU beforeACR is decreased into ICR, and can take value ranging from 1 to 1023(unit is 10 mili sec.). According as this value is caused to be greatervalue, the current rate can be resultantly maintained for a long time.Default value is 50 (500 ms).

The status transition in Reset of User side of FIG. 12 will now bedescribed with reference to the flowchart of FIG. 23. The processing ofsteps S1 to S10 of FIG. 23 are the processing in the case of carryingout transition from the status of Reset to the status of ActPending, andthe processing of steps S13 to S19 are the processing in the case ofcarrying out transition to the status of Reset for a second time. Theroutes (paths) corresponding to the processing of the steps S11, S12 arenot shown in FIG. 12.

When primitive of MASEL_Act_Req is received from ASEL layer managementat step S1, ASEL-CME judges at step S2 whether or not ASEL-UNI IDalready exists. In the case where this ID does not yet exist, theprocessing operation proceeds to step S3, at which ASEL-CME setsASEL-UNI ID at aselLayerUniId.

Then, the processing operation proceeds to step S4, at whichaselLayer1394BusIndex is set. Further, at step S5,aselLayerUserSideNodeUniqId and aselLayerUserSideNodeSelfId are set. Inthis example, in the case where it is judged at the step S2 thatASEL-UNI ID already exist, the processing of the steps S3 to S5 areskipped.

Then, the processing operation proceeds to step S6, at which ReferenceID is incremented. Thereafter, at step S7, message of WakeUp isoutputted to ASEL-CME of Network side. At step S8, ActPending is set ataselLayerStatus. Then, at step S9, Timer_Reset is stopped. At step S10,Timer_ActPending is started. Then, transition to the status ofActPending is carried out.

When local event of Timer_Reset Expire (expiration) is received at stepS13, the processing operation proceeds to step S14, at which transmitprocessing of local event of recovery stop from Reset is carried out.Then, the processing operation proceeds to step S15, at which ASEL-VCCon corresponding ASEL-UNI is retrieved. At step S16, whether or notretrieval is completed is judged. If the retrieval is not completed, theprocessing operation proceeds to step S17, at which processing forreleasing all resources relating to the retrieved ASEL-VCC is executed.Thereafter, the processing operation returns to the step S15. Theprocessing of the step S15 and steps subsequent thereto will berepeatedly executed.

In the case where it has been judged at the step S16 that retrieval hasbeen completed, the processing operation proceeds to step S18, at whichaselLayerUniId, aselLayer1394BusIndex, aselLayerNetSideNodeUniqId,aselLayerUserSideNodeUniqId are respectively cleared. Thereafter, theprocessing operation proceeds to step S19, at which primitive ofMASEL_BusHalt.Ind is outputted with respect to the ASEL layermanagement. Thus, there results the status of Reset (the system controlstatus returns to the Status of Reset) for a second time. Afterprimitive of MASEL_BusHalt.Ind is received, the application softwareimmediately releases resources relating to all VCCs on ASEL_UNI.

On the other hand, in the case where recoverable local event from Resetis received at step S11, the processing operation proceeds to step S12.Thus, whether or not ASEL-UNIID already exists is judged. If ASEL-UNIIDdoes not exist, there results the status of Reset (the system controlstatus returns to the status of Reset) for a second time. If ASEL-UNIIDexists, the processing operation proceeds to step S6, at which theprocessing of the step S6 and processing subsequent thereto areexecuted. Thus, transition to the status of ActPending is carried out.

The status transition of ActPending will now be described with referenceto FIG. 24. Processing of steps S31 to S38 indicate processing in thecase where transition is carried out from the status of ActPending tothe status of Act, and processing of steps S39 to S46 indicateprocessing in the case where the system control status returns from thestatus of ActPending to status of ActPending for a second time.

When PDU of ActReq is received from ASEL-CME of Network side at stepS31, whether or not Reference ID is True is checked at step S32. In thecase where this ID is True, the processing operation proceeds to stepS33, at which aselLayerNetSideNode UniqId and aselLayerNetSideNodeSelfIdare set. At step S34, PDU of ActAck is transmitted to ASEL-CME ofNetwork side. At step S35, MASEL_Act.Ind is transmitted with respect tothe ASEL layer management.

Then, the processing operation proceeds to step S36, at whichTimer_ActPending is stopped. At step S37, 0 is set with respect to K. Atstep S38, Act is set at aselLayerStatus. Then, transition to the statusof Act is carried out.

At step S32, in the case where Reference ID is judged to be False, thereresults the status of ActPending for a second time (the system controlstatus returns to the status of ActPending).

In the case where local event indicating that Timer_ActPending has beenexpired is received at step S39, the processing operation proceeds tostep S40, at which K is incremented. This K indicates the number ofexpire operations of Timer_ActPending. Then, at step S41, whether or notK is greater than aselLayerMaxTimerExpire is judged. In the case whereit is judged that K is greater than aselLayerMaxTimerExpire, theprocessing operation proceeds to step S45, at which MASEL_expireEr.Indis outputted with respect to the ASEL layer management. At step S46, 0is set with respect to K. Thus, there results the status of ActPendingfor a second time (the system control status returns to the status ofactpending).

In the case where it is judged at the step S41 that K andaselLayerMaxTimerExpire are equal to each other, or K is smaller thanthe latter, the processing operation proceeds to step S42. Thus,Timer_ActPending is re-started. At step S43, 0x81 is set at Error Code.At step S44, message of WakeUp is transmitted (is re-transmitted) toASEL-CME of Network side as PDU. Thus, there results the status ofActPending for a second time (the system control status returns to thestatus of Actpending).

The processing in the case where the system control status returns tothe status of Act for a second time from the status of Act will now bedescribed with reference to FIGS. 25 and 26.

In FIG. 25, when MASEL_ConSet.Req is received from ASEL layer managementat step S61, aselVccConnId, aselVccVpi, aselVccVci, aselvccAalType,aselVccQosType, aselVccTransmitSegLen, aselVccReceiveSeqNum,aselVccOprSpeed, aselAalConn objects are set at step S62. Then, theprocessing operation proceeds to step S63, at which whether or notaselVccQosType is set at CBR is judged. In the case where theaselVccQosType is set at CBR, the processing operation proceeds to stepS64, at which aselVccIsoDelayVariationTolerance, aselVccIsoTransmitBand,aselVccIsoReceiveBand are set. Then, at step S65, IsoReq is transmittedto ASEL-CME of Network side as PDU. Thus, there results the status ofAct for a second time (the system control status returns to the statusof Act).

In the case where it is judged at the step S63 that CBR is not set ataselVccQosType, the processing operation proceeds to step S66, at whichaselVccAsyncPeakTransmitRate, aselVccAsyncPeakReceiveRate are set. Then,at step S67, whether or not ABR is set at aselVccQosType is judged. Inthe case where it is judged that ABR is not set at aselVccQosType, theprocessing operation proceeds to step S69, at which PDU of DestIDReq istransmitted to ASEL-CME of Network side. Thus, there results the statusof Act for a second time (the system control status returns to status ofAct).

In the case where it is judged at the step S67 that ABR is set ataselVccQosType, the processing operation proceeds to step S68, at whichaselVccAbrVpi, aselVccAbrVci, aselVccAbrMinTransmitRate,aselVccAbrMinReceiveRate, aselVccAbrInitialTransmitRate,aselVccAbrInitialReceiveRate, aselVccAbrAllowedTransmitRate,aselVccAbrAllowedReceiveRate, aselVccAbrTransmitCdf,aselVccAbrTransmitRif, aselVccAbrTransmitRdf, aselVccAbrTransmitAtdf arerespectively set. Thereafter, the processing operation proceeds to stepS69 to output PDU of DestIDReq to ASEL-CME of Network side. Thus, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

When, MASEL_ConRec.Req is received from ASEL layer management at stepS70, the processing operation proceeds to step S69 to transmit DestIDReqto ASEL-CME of Network side. Thus, there results the status of Act for asecond time (the system control status returns to the status of Act).

When PDU of IsoRply is received from ASEL-CME of Network side at stepS71, the processing operation proceeds to step S72, at which whether ornot serious (fatal) error takes place is judged. In the case where ithas been judged that serious (fatal) error takes place, the processingoperation proceeds to step S76, at which MASEL_FatalEr.Ind (ErrorCode iscaused to be A C2h) is outputted with respect to the ASEL layermanagement. Thus, there results the status of Act for a second time (thesystem control status returns to the status of Act).

In the case where it is judged at the step S72 that serious (fatal)error does not take place, the processing operation proceeds to stepS73, at which aselVccIsoChannel, aselVccOprSpeed are set. At step S74,Up is set at aselVccStatus. Then, at step S75, MASEL_ConSet.Conf isoutputted to ASEL layer management. Thus, there results the status ofAct for a second time (the systemm control status returns to the statusof Act).

When DestIDRply is received from ASEL-CME of Network side at step S77,the processing operation proceeds to step S78, at which whether or notserious (fatal) error takes place is judged. In the case where it hasbeen judged that serious (fatal) error takes place, the processingoperation proceeds to step S82, at which MASEL_FatalEr.Ind (ErrorCode iscaused to be C3h) is outputted with respect to the ASEL layermanagement. Thus, there results the status of Act for a second time (thesystem control status returns to the status of Act).

In the case where it has been judged at the step S78 that serious(fatal) does not take place, the processing operation proceeds to stepS79, at which aselVccAsyncDestID and aselVccOprSpeed are set. At stepS80, Up is set at aselVccStatus. Further, at step S81, MASEL_ConSet.Confis outputted with respect to the ASEL layer management. Thus, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

In FIG. 26, when ActReq is received from ASEL-CME of Network side atstep S91, whether or not Reference ID is True is judged at step S92. Inthe case where this ID is judged to be True, the processing operationproceeds to step S93, at which 0 is set at Error Code. At step S94,ActAck is transmitted to ASEL-CME of Network side. Then, at step S95,MASEL_StsEr.Ind is outputted to ASEL layer management. Thus, thereresults the status of Act for a second time (the system control statusreturns to the status of Act). In the case where it has been judged atstep S92 that Reference ID is False, the processing of steps S93 to S95are skipped. Thus, there immediately results the status of Act (thesystem control status immediately returns to the status of Act).

Further, in any (arbitrary) status (status of ActPending or Act) exceptfor Reset shown in FIG. 12, processing shown in the flowchart of FIG. 27is carried out. Thus, transition to the status of Reset takes place.

Namely, when MASEL_Reset.Req is received from the ASEL layer managementat step S101, ASEL-VCC in Asynchronous Link on corresponding ASEL-UNI isretrieved at step S102. At step 103, whether or not this retrieval iscompleted is judged. If this retrieval is not completed, the processingoperation proceeds to step S108, at which down is set at aselVccStatus.Then, at step S109, aselVccAsyncDestId is cleared, and the processingoperation returns to the step S102. Thus, the processing of the stepS102 and steps subsequent thereto will be repeatedly executed.

In the case where it is judged at step S103 that retrieval is completed,the processing operation proceeds to step S104, at whichaselLayerUserSideSelfId and aselLayerNetSideSelfId are cleared. At stepS105, Reset is set at aselLayerStatus. At step S106, Timer_Reset isstarted. Further, at step S107, local event in recovery starting statefrom Reset is transmitted. Thus, transition to the status of Reset iscarried out.

Moreover, in all of three statuses of FIG. 12, processing shown in FIG.28 is carried out. Namely, when MASEL_ConRel.Req is received from ASELlayer management at step S121, the processing operation proceeds to stepS122, at which all parameters in corresponding ASEL-VCC are cleared.Then, at step S123, MASEL_ConRel.Conf is outputted to the ASEL layermanagement. Thus, there results the original status (the system controlstatus returns to the original status).

Explanation will now be given with reference to the flowcharts of FIGS.29 to 35 in connection with the status transition in three statuses ofNetwork side of FIG. 13. FIG. 29 shows processing carried out in any oneof three statuses of FIG. 13. Initially, when WakeUp is received fromASEL-CME of User side at step S131, aselLayerNetSideNodeSelfID andaselLayerUserSideNodeSelfID are cleared at step S132. Then, theprocessing operation proceeds to step S133, at which whether or notNU_ID of terminal of User side which has transmitted WakeUp message isnew NU_ID of User side different from NU_ID until that time is judged.

In the case where it is judged that corresponding NU_ID is new NU_ID ofUser side, the processing operation proceeds to step S134, at whichassignment processing of aselLayerUniID caused to be in relevancy toNU_ID of User side is executed. Then, the processing operationprocessing proceeds to step S135, at which 1394 Bus Index in LK_DATA.indis set at aselLayer1394BusIndex. At step S13 ,aselLayerNetSideNodeUniqId, aselLayerUserSideNodeUniqId are set. In thecase where it is judged at the step S133 that NU_ID of terminal of Userside which has transmitted WakeUp message is not new NU_ID of User side,the above-mentioned processing of steps S134 to S136 are skipped.

Then, the processing operation proceeds to step S137, at whichaselLayerUserSideNodeSelfId, aselLayerNetSideNodeSelfId are set. At stepS138, Reference ID is preserved (stored). Further, at step S139,ActPending is set at aselLayerStatus. At step S140, ActReq istransmitted to ASEL-CME of User side. At step S141, Timer_Reset isstopped. In addition, at step S142, after Timer_ActPending is started,transition to the status of ActPending is carried out.

Namely, in this way, processing of transition or return from the statusof Reset, the status of Act or the status of ActPending to the status ofActPending is carried out.

FIG. 30 shows processing in the case where the system control statusreturns, from the status of Reset of FIG. 13, to that status for asecond time. In this processing, initially, when local event ofTimer_Reset expire is received at step S151, ASEL-VCC on correspondingASEL-UNI is retrieved at step S152. Then, at step S153, whether or notretrieval is completed is judged. If retrieval is not completed, theprocessing operation proceeds to step S154, at which processing forreleasing all resources relating to the retrieved ASEL-VCC is executed.Then, the processing operation returns to the step S152. Thus,processing at this step and steps subsequent thereto are repeatedlyexecuted.

In the case where it is judged at the step S153 that retrieval iscompleted, the processing operation proceeds to step S155, at whichaselLayerUniId, AselLayer1394BusIndex, aselLayerNetSideNodeUniqId,aselLayerUserSideNodeUniqId are cleared. Then, at step S156,MASEL_BusHalt.Ind is outputted to ASEL layer management. Thus, thereresults the status of Reset for a second time (the system control statusreturns to the status of Reset. When MASEL_BusHalt.Ind is outputted toASEL layer management at the step S156, application software releases,after this primitive is received, resource relating to all VCCs onASEL-UNI similarly to the case at the step S19 of FIG. 23.

Explanation will now be given with reference to FIG. 31 in connectionwith processing in the case where transition from the status ofActPending of FIG. 13 to the status of Act is carried out (steps S161 toS167) and processing in the case where the system control statusreturns, from the status of ActPending, to that status for a second time(steps S161, S162, S163 and S168 to S176).

When ActAck is received from ASEL-CME of User side at step S161, checkof Reference ID is carried out at step S162. In the case where it isjudged that Reference ID is True, the processing operation proceeds tostep S163, at which whether or not serious (fatal) error takes place isjudged. In the case where serious (fatal) error does not take place, theprocessing operation proceeds to step S164, at which Act is set ataselLayerStatus. Then, at step S165, MASEL_ACT.Ind is outputted to ASELlayer management. At step S166, Timer_ActPending is stopped. At stepS167, 0 is set with respect to K. Thus, transition to the status of Actis carried out.

In the case where it is judged at the step S162 that Reference ID isFalse, transition to the status of ActPending is immediately carriedout. Moreover, in the case where it is judged at the step S163 thatserious (fatal) error takes place, the processing operation proceeds tostep S168. Thus, after MASEL_FatalEr.Ind (Error Code is caused to beC1h) is outputted to ASEL layer management, transition to the status ofActPending is carried out.

In the case where event of Timer_ActPending expire is received at stepS169, the processing operation proceeds to step S170, at which parameterK equal to the number of expire operations of Timer_ActPending isincremented by 1. Thereafter, the processing operation proceeds to stepS171, at which whether or not K is greater than aselLayerMaxTimerExpireis judged. In the case where it is judged that K is greater thanaselLayerMaxTimerExpire, the processing operation proceeds to step S175,at which MASEL-ExpireEr.Ind is outputted to ASEL layer management.Thereafter, at step S176, 0 is set with respect to K. Thus, thereresults the status of ActPending for a second time (the system controlstatus returns to the status of ActPending).

In the case where it is judged at the step S171 that value of K is equalto aselLayerMaxTimerExpire or is smaller than that, the processingoperation proceeds to step S172, at which processing for re-startingTimer_ActPending is carried out. Then, at step S173, 0x81 is set atError Code. At step S174, ActReq is transmitted (re-transmitted) toASEL-CME of User side. Thus, there results the status of ActPending fora second time (the system control status returns to the status ofActPending).

Explanation will now be given with reference to the flowcharts of FIGS.32 and 33 in connection with the processing in the case where the systemcontrol status returns, from the status Act of FIG. 13, to that statusfor a second time.

When MASEL_ConSet.Req is received from ASEL layer management in thestatus of Act at step S191 of FIG. 32, the processing operation proceedsto step S192, at which aselVccConnId, aselVccVpi, aselVccVci,aselVccRouteArea, aselVccTopology, aselVccAalType, aselVccQosType,aselVccTransmitSegLen, aselVccReceiveSeqNum, aselVccOprSpeed,aselAalConn objects are set.

Then, the processing operation proceeds to step S193, at which whetheror not CBR is set at aselVccQosType is judged. In the case where it isjudged that CBR is set at aselVccQosType, the processing operationproceeds to step S194, at which aselVccIsoDelayVariationTolerance,aselVccIsoTransmitBand, aselVccIsoReceiveBand are set. Then, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

In the case where it is judged at the step S193 that CBR is not set ataselVccQosType, the processing operation proceeds to step S195, at whichaselVccAsyncPeakTransmitRate, aselVccAsyncPeakReceiveRate are set. Then,the processing operation proceeds to step S196, at which whether or notaselVccQosType is ABR is judged. In the case where aselVccQosType isABR, the processing operation proceeds to step S197, at whichaselVccAbrVpi, aselVccAbrVci, aselVccAbrMinTransmitRate,aselVccAbrMinReceiveRate, aselVccAbrInitialTransmitRate,aselVccAbrInitialReceiveRate, aselVccAbrAllowedTransmitRate,aselVccAbrAllowedReceiveRate are set. In the case where it is judged atthe step S196 that aselVccQosType is not ABR, the processing of the stepS197 is skipped. Thus, there results the status of Act for a second time(the system control status returns to the status of Act).

When IsoReq is received from ASEL-CME of User side at step S198 in thestatus of Act, the processing operation proceeds to step S199, at whichconfirmation of available Isochronous channel is carried out. Then, atstep S200, whether or not available Isochronous channel exists isjudged. In the case where it is judged that available Isochronouschannel exists, the processing operation proceeds to step S201, at whichcorresponding channel is set with respect to aselVccIsoChannel. At stepS202, Up is set at aselVccStatus. Then, at step S203, IsoRply istransmitted to ASEL-CME of User side. At step S204, MASEL_Con.Set.Confis outputted with respect to ASEL layer management. Thereafter, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

In the case where it is judged at the step S200 that availableIsochronous channel does not exist, the processing operation proceeds tostep S205, at which 0x2 is set at Error Code. At step 206, IsoRplyindicating that Iso channel does not exist is transmitted to ASEL-CME ofUser side. At step S207, MASEL_IsoEr.Ind is outputted with respect toASEL layer management. Thus, there results the status of Act for asecond time (the system control status returns to the status of Act).

In the case where DestIDReq is received from ASEL-CME of User side atstep S208, the processing operation proceeds to step S209, at whichretrieval processing of Destination SelfID is carried out. At step S210,whether or not Destination SelfID is retrieved (found) is judged. In thecase where Destination SelfID is retrieved, the processing operationproceeds to step S211, at which its result is set at aselVccAsyncDestID.At step S212, Up is further set at aselVccStatus. At step S213,DestIDRply is transmitted to ASEL-CME of User side. Further, at stepS214, MASEL_ConSet.Conf is outputted to ASEL layer management. Thus,there results the status of Act for a second time (the system controlstatus returns to the Status of Act).

In the case where it is judged at step S210 that Destination SelfID isnot retrieved, the processing operation proceeds to step S215, at which0xC3 is set with respect to Error Code. At step S216, DestIDRplyindicating that Destination ID cannot be found is transmitted toASEL-CME of User side. Further, at step S217, MASEL_DestIDEr.Ind isoutputted to ASEL layer management. Thereafter, there results the statusof Act for a second time (the system control status returns to thestatus of Act).

In FIG. 33, when ActAck is received from ASEL-CME of User side at stepS231, whether or not Reference ID is True is judged at step S232. In thecase where this ID is True, the processing operation proceeds to stepS233, at which whether or not serious (fatal) error takes place isjudged. In the case where it is judged that serious (fatal) error takesplace, the processing operation proceeds to step S235, at whichMASEL_FatalEr.Ind (C1h is set at Error Code) is outputted to ASEL layermanagement. Thus, there results the status of Act for a second time (thesystem control status returns to the status of Act).

In the case where it is judged at the step S233 that serious (fatal)error does not take place, the processing operation proceeds to stepS234, at which MASEL_StsEr.Ind is outputted to ASEL layer management.Thereafter, there results the status of Act for a second time (thesystem control status returns to status of Act).

In the case where it is judged at the step S232 that Reference ID isFalse, the processing of steps S233 to S235 are skipped. Thus, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

Further, in the status except for Reset of FIG. 13, i.e., in the statusof Actpending or the status of Act, processing of transition to Reset iscarried out by processing of FIG. 34.

In this case, when MASEL_Reset.Req is received from ASEL layermanagement at step S241, processing for retrieving ASEL-VCC inAsynchronous Link on corresponding ASEL-UNI is carried out at step S242.At step S243, whether or not retrieval has been completed is judged. Inthe case where retrieval has not yet been completed, the processingoperation proceeds to step S244, at which down is set at aselVccStatus.After aselVccAsyncDestID is cleared at step S245, the processingoperation returns to the step S242. Thus, processing at the step S242and those at steps subsequent thereto are repeatedly executed.

In the case where it is judged at the step S243 that retrieval has beencompleted, the processing operation proceeds to step S246, at whichaselLayerUserSideSelfId and aselLayerNetSideSelfId are cleared. At stepS247, Reset is set with respect to aselLayerStatus. At step S248,Timer_Reset is started. Thereafter, transition to the status of Reset iscarried out.

Further, in any (arbitrary) status of three statuses of FIG. 13,processing indicated by the flowchart of FIG. 35 is carried out. In thiscase, when MASEL_ConRel.Req is received from ASEL layer management atstep S261, all parameters in corresponding ASEL-VCC are cleared at stepS262. Then, at step S263, MASEL_ConRef.Conf is outputted to ASEL layermanagement. Thereafter, there results the original status for a secondtime (the system control status returns to the original status).

Explanation will be given with reference to the flowcharts of FIGS. 36to 43 in connection with the processing in the case of transmitting datafrom Upper Layer of FIG. 6 to 1394 Link layer, or from ASEL layermanagement to 1394 Link layer.

FIGS. 36 and 37 show processing in the case where LK_ISO.req orLK_DATA.req is outputted to 1394 Link layer when ASEL receives input ofALL_UNITDATA.Req from Upper Layer.

Initially, at step S281, in the status of Act, AAL_UNITDATA.Req isreceived from Upper Layer. In this AAL_UNITDATA.Req, ASEL-UNI ID,VPI/VCI Value, AAL-ID, More, AAL-LP, ALL-CI, AAL-UU, AAL-ES areincluded.

Then, the processing operation proceeds to step S282, at which check asto whether or not aselVccVpi and aselVccVci corresponding to ASEL-UNI IDand VPI/VCI Value exist is carried out. In the case where it is judgedthat result of this check is True, the processing operation proceeds tostep S283, at which whether or not aselVccStatus is Up is judged. In thecase where Up is set with respect to aselVccStatus, the processingoperation proceeds to step S284, at which value of aselVccVpi is setwith respect to VPI Value of ASEL header and value of aselVccVci is setwith respect to VCI Value. In this example, in the case where result ofthe check was False at the step S282, or in the case where it was judgedat the step S283 that Up is not set with respect to aselVccStatus, thereresults the status of Act for a second time (the system control statusreturns to the status of Act).

Then, at step S285, aselVccQosType is set at QoS class. At step S286,whether or not QoS class is CBR is judged. In the case where it isjudged that QoS class is CBR, the processing operation proceeds to stepS287, at which parameter preparation processing of primitive ofLK_ISO.req is executed. The detail of this processing will be describedlater with reference to the flowchart of FIG. 40.

In the case where it is judged at the step S286 that QoS class is notCBR, the processing operation proceeds to step S288, at which parameterpreparation processing of primitive of LK_DATA.req is executed. Thedetail of this processing will be described later with reference to theflowchart of FIG. 41.

Then, the processing operation proceeds to step S289, at which TR_SN isset at SN. In this example, this parameter SN indicates Sequence Numbervalue at the transmitting side, and has independent values everyrespective ASEL-VCCs. In addition, TR_SN is parameter incremented atstep S307 as described later.

Then, at step S290, 0 is set with respect to MI. At step S291, 0 is setwith respect to MNG-ID.

At step S292, whether aselVccAalType is either AAL5 or AAL0 is judged.In the case where it is judged that aselVccAalType is AAL5, theprocessing operation proceeds to step S293, at which AAL5 is set atAAL_Type. Then, at step S294, parameter preparation processing of AAL5Specific field is executed. The detail of this processing will bedescribed later with reference to the flowchart of FIG. 42.

Then, at step S295, pointer to buffer in which AAL-ID is stored is setat ptrSDU. At step S296, length of AAL-ID is set at Count. At step S297,whether or not value of Count is greater than value obtained bysubtracting 8 from aselVccTransmitSegLen is judged. At this time, in thecase where judgement of No is carried out, the processing operationproceeds to step S297A, at which whether More is “Not Used (i.e.,unused) or “End of SDU” (i.e., including the last portion of AAL-SDU) isjudged. In the case where it is judged that More is “Not Used” or “Endof ADU”, the processing operation proceeds to step S298, at which 0 isset with respect to MR. At step S301, value obtained by adding 8 toCount is set at Data Length.

Further, at step S302, whether or not QoS class is CBR is judged. Atthis time, in the case where judgment of Yes is carried out, theprocessing operation proceeds to step S303, at which LK_ISO.req isoutputted to 1394 Link layer. Thereafter, there results the status ofAct for a second time (the system control status returns to the statusof ACT). In the case where it is judged at the step S302 that QoS classis not CBR, LK_DATA.Req is outputted to 1394 Link layer at step S304.Thereafter, there results the status of Act for a second time (thesystem control status returns to the status of Act).

In the case where it is judged at the step S292 that aselVccAalType isAAL0, the processing operation proceeds to step S299, at which AAL0 isset at (with respect to) AAL-Type. Then, at step S300, parameterpreparation processing of AAL0 Specific field is executed. The detail ofthis processing will be described later with reference to the flowchartof FIG. 43. Thereafter, the processing operation proceeds to step S301.Thus, the processing of the step S301 and processing subsequent theretoare executed.

On the other hand, in the case where it is judged at the step S297 thatvalue of Count is greater than value obtained by subtracting 8 fromaselVccTransmitSegLen, the processing operation proceeds to step S305,at which 1 is set with respect to MR. Then, at step S306, value ofaselVccTransmitSegLen is set at Data length. At step S307, value ofTR_SN is incremented. At step S308, whether or not QoS class is CBR isjudged. In the case where judgment of Yes is carried out at this step,the processing operation proceeds to step S309, at which LK_ISO.req isoutputted to 1394 Link layer. In the case where judgment of No iscarried out at the step S308, LK_DATA.req is outputted to 1394 Linklayer a step S310.

Then, the processing operation proceeds to step S311, at which valueobtained by subtracting 8 from aselVccTransmitSegLen is added to currentvalue of ptrSDU. Then, the processing operation proceeds to step S312,at which value of Count is decremented by value obtained by subtracting8 from aselVccTransmitSegLen. Thereafter, the processing operationreturns to the step S297. Thus, the processing of the step S297 andsteps subsequent thereto are repeatedly executed.

Also in the case where it is judged at the step S297A that More is not“Not Used” or “End of PDU”, the processing operation proceeds to thestep S305. Thus, the processing of the step S305 and steps subsequentthereto are carried out.

FIG. 38 shows the processing that ASEL outputs LK_DATA.req with respectto 1394 Link layer when MASEL_DATA.Req is received from ASEL layermanagement in FIG. 6.

Namely, in the status of Act, at step S321, MASEL_DATA.Req is receivedfrom ASEL layer management. In this MASEL_DATA.Req, ASEL-UNI ID, VPI/VCIValue, MNG-ID, AAL-ID(SDU), AAL-LP, AAL-CI, AAL-ES are included.

Then, at step S322, whether or not aselVccVpi and aselVccVcicorresponding to each other exist is judged. In the case whereaselVccVpi and aselVccVci exist, the processing operation proceeds tostep S323, at which whether or not Up is set at aselVccStatus is judged.In the case where judgment of Yes is carried out at the step S323, theprocessing operation proceeds to step S324, at which value of aselVccVpiis set at VPI Value of ASEL header and value of aselVccVci is set at VCIValue. At step S325, value of aselVccQosType is set at QoS Class. Atstep S326, parameter preparation processing of primitive of LK_DATA.req(detail of this processing will be described later with reference toFIG. 41) is executed.

Then, at step S327, TR_SN is set at (with respect to) SN. At step S328,1 is set with respect to MI. Further, at step S329, value of MNG-ID inMASEL_DATA.req is set at (with respect to) MNG-ID. At step S330, AAL0 isset with respect to AAL_Type.

Then, at step S331, parameter preparation processing of AAL0 SpecificField (detail of this processing will be described later with referenceto FIG. 43) is executed.

Then, at step S332, value obtained by adding 8 to length of AAL-SDU isset with respect to Data length. At step S333, LK_DATA.req is outputtedto 1394 Link layer. Thereafter, there results the status of Act for asecond time (the system control status returns to status of Act).

In the case where it is judged at the step S322 that aselVccVpi andaselVccVci are False, processing is not particularly carried out. Thus,there results the status of Act for a second time (the system controlstatus returns to the status of Act). Also in the case where it isjudged at the step S323 that Up is not set at acelVccStatus, processingsimilar to the above is conducted.

FIG. 39 represents transfer processing of ASEL-CMP carried out inarbitrary status. When local event of request for transmission ofASEL_CMP is received at step S351, 0 is set with respect to QoS class atstep S352. At step S353, value of aselLayer 1394 BusIndex is set withrespect to 1394 Bus Index. At step S354, 0 (zeros) are respectively setwith respect to VPI Value and VCI Value of ASEL header.

Then, at step S355, whether aselLayeroprMode is User side or Networkside is judged. In the case where it is judged that aselLayerOprMode isUser side, the processing operation proceeds to step S356, at whichaselLayerNetSideNodeSelfId is set with respect to Destination SelfID. Inthe case where it is judged at the step S355 that aselLayerOprMode isNetwork side, the processing operation proceeds to step S357, at whichaselLayerUserSideNodeSelfId is set with respect to Destination SelfID.

Then, the processing operation proceeds to step S358, at which 1 is setwith respect to Transaction Code. At step S359, 1 is set with respect toRetry Code. At step S360, value of AselVccOprSpeed is set with respectto Speed. At step S361, TR_SN is set with respect to SN. At step S362, 1is further set with respect to M1. At step S363, 0 is set with respectto MNG-ID. At step S364, AAL0 is set with respect to AAL-Type.

Further, at step S365, 0 is set with respect to MR. At step S366, 0 isset with respect to LP. At step S367, 0 is set with respect to CI. Atstep S368, 0 is set with respect to EI. At step S369, 0 is set withrespect to ER-ID. Then, at step S370, value obtained by adding 8 tolength of ASEL_CMP is set with respect to Data length. At step S371,LK_DATA.req is outputted to 1394 Link layer. Thus, there results theoriginal status for a second time (the systemm control status returns tothe original status).

Explanation will now be given with reference to FIGS. 40 to 43 inconnection with more detailed processing of the subroutine included inthe above-described processing of FIGS. 36 and 38. FIG. 40 shows thedetail of the parameter preparation processisng of LK_ISO.req primitiveof the step S287 of FIG. 36. In this processing, initially, at stepS391, value of aselLayer1394BusIndex is first set with respect to 1394Bus Index. At step S392, value of the low order 6 bits ofaselVccIsoChannel is set with respect to Isochronous Channel number.Further, at step S393, value of the high order 2 bits ofaselVccIsoChannel is set with respect to Tag value. At step S394, valueof aselVccOprSpeed is set with respect to Speed.

FIG. 41 shows the detail of the parameter preparation processing ofLK_DATA.req primitive at the step S288 of FIG. 36 and the step S326 ofFIG. 38. Initially, at step S401, value of aselLayer1394BusIndex is setwith respect to 1394 Bus Index. At step S402, value ofaselVccAsyncDestId is set with respect to Destination SelfID. Further,at step S403, value of aselLayer1394DestOffset is set with respect toDestination offset. At steps S404 and S405, values of 1 are respectivelyset with respect to Transaction Code and Retry code. Then, at step S406,value of aselVccOprSpeed is set with respect to Speed.

FIG. 42 shows the detail of the parameter preparation processing of AAL5Specific field at the step S294 of FIG. 36. At step S411, value ofAAL-LP is set with respect to LP. This parameter is caused to undergomapping from AAL_UNITDATA.req primitive. Then, at step S412, AAL-CI isset with respect to CI. This parameter is also caused to undergo mappingfrom AAL_UNITDATA.req primitive.

Then, at step S414, whether or not ES is No Error is judged. At thistime, in the case where judgment of Yes is carried out, the processingoperation proceeds to step S415, at which 0 is set with respect to EI.At step S416, 0 is set with respect to ER-ID.

In the case where judgment of No is carried out at the step S414, theprocessing operation proceeds to step S417, at which 1 is set withrespect to EI. Then, at step S418, whether or not ES is CPCS CRC erroris judged. In the case of Yes, the processing operation proceeds to stepS419, at which 0x81 is set with respect to ER-ID.

In the case where judgment of No is carried out at the step S418, theprocessing operation proceeds to step S420, at which whether or not ESis CPCS-SDU Length error is judged. In the case where judgment of Yes iscarried out, the processing operation proceeds to step S421, at which0x82 is set with respect to ER-ID. In the case where judgment of No iscarried out at the step S420, the processing operation proceeds to stepS422, at which 0 is set with respect to ER-ID.

FIG. 43 shows the detail of the parameter preparation processing of AAL0Specific field at the step S300 of FIG. 36 and at the step S331 of FIG.38. At step S431, 0 is set with respect to MR. At step S432, AAL-LP isset with respect to LP. At step S433, AAL-CI is set with respect to CI.At step S434, whether or not ES is No Error is judged. At this time, inthe case where judgment of Yes is carried out, the processing operationproceeds to step S435, at which 0 is set with respect to EI. At stepS436, 0 is set with respect to ER-ID.

In the case where judgment of No is carried out at the step S434, theprocessing operation proceeds to step S437, at which 1 is set withrespect to EI. Then, at step S438, 0x01 is set with respect to ER-ID.

The flowcharts of FIGS. 44 to 46 represent the processing for receivinginput of LK_DATA.Ind or LK_ISO.Ind from the 1394 Link layer of FIG. 6 tooutput AAL_UNITDATA.ind to Upper Layer, or to output MASEL_DATA.Ind withrespect to ASEL layer management.

In an arbitrary (any) status, at step S451, LK_DATA.Ind is received from1394Link layer. In this LK_DATA.Ind, 1394 Bus Index, Source selfID,Destination SelfID, Destination Offset, Transaction code, Retry code,Data Length, Data (ASEL-PDU), Speed, Packet Status are included.

Then, the processing operation proceeds to step S452, at which checkprocessing of 1394 Asynchronous header format is carried out. The detailof this processing will be described later with reference to theflowchart of FIG. 47. Then, the processing operation proceeds to stepS453, whether or not Result is OK is judged. In the case where Result isnot OK, the processing operation proceeds to step S465. In the casewhere Result is OK, the processing operation proceeds to step S454, atwhich retrieval processing of ASEL-UNI ID using 1394 Bus Index andSource SelfID is carried out.

Then, at step S455, whether or not ASEL-UNI ID is retrieved is judged.In the case where ASEL-UNI ID is retrieved, the processing operationproceeds to step S456, at which check of VPI/VCI Value of ASEL header iscarried out. In the case where this value is correct and VPI/VCI are not0/0, the processing operation proceeds to step S457. In the case wherethis value is correct and VPI/VCI are 0/0, the processing operationproceeds to step S475. In the case where this value is not correct, theprocessing operation proceeds to step S465. In this case, the fact thatVPI/VCI are 0/0 indicate that VPI Value is zero (0) and VCI Value isalso zero (0).

In the case where it is judged at the step S455 that ASEL-UNI ID is notretrieved, the processing operation proceeds to step S467, at whichwhether or not VPI/VCI are both zero (0) is judged. In the case wherejudgment of Yes is carried out at the step S467, the processingoperation proceeds to step S475. In the case where judgment of No iscarried out, the processing operation proceeds to step S465.

At step S457, whether or not MI is zero (0) is judged. At this time, inthe case where judgment of Yes is carried out, the processing operationproceeds to step S458, at which judgment of AAL Type is carried out. Inthe case where AAL Type is Type0, the processing operation proceeds tostep S459. In the case where AAL Type is Type 5, the processingoperation proceeds to step S479. In the case where AAL Type is any otherType, the processing operation proceeds to step S465.

At the step S459, composing processing of AAL0 (User data) is carriedout. The detail of the processing will be described later with referenceto the flowchart of FIG. 50. Then, the processing operation proceeds tostep S460, at which whether or not Result is OK is judged. In the casewhere it is judged that Result is OK, the processing operation proceedsto step S461, at which the processing for adding (supplementing)ASEL_SDU i.e., AAL-SDU) into receiving buffer is executed. Then, theprocessing operation proceeds to step S462. Thus, the preparationprocessing of AAL0 parameter is executed. The detail of this processingwill be described later with reference to the flowchart of FIG. 53.Then, the processing operation proceeds to step S463. Thus,AAL_UNITDATA.Ind is outputted to Upper Layer of FIG. 6. In thisAAL_UNIDATA.Ind, ASEL-UNI ID, VPI/VCI value, AAL-ID(SDU), AAL-LP,AAL-CI, AAL-ES are included. Then, there results the original status fora second time (the system control status returns to the originalstatus).

In the case where it is judged at the step S460 that Result is NG, theprocessing operation proceeds to step S464, at which No error is setwith respect to RCV_ER_Status. This parameter represents error status ofAAL-SDU being received, and has independent values every respectiveASEL-VCCs. Thereafter, the processing operation proceeds to step S465.

In the case where it is judged at the step S457 that value of MI is notzero (0), the processing operation proceeds to step S468, at whichwhether or not MNG ID is zero (0) is judged. At this time, in the casewhere judgment of Yes is carried out, the processing operation proceedsto step S475. On the contrary, in the case where judgment of No iscarried out, the processing operation proceeds to step S469. At the stepS469, whether or not AAL Type is zero (0) is judged. In the case wherejudgment of No is carried out at this step, the processing operationproceeds to the step S465. In the case where judgment of Yes is carriedout at this step, the processing operation proceeds to step S470, atwhich composing processing of AAL0 (LM data) is executed. The detail ofthis processing will be described later with reference to the flowchartof FIG. 51.

Then, at step S471, whether or not Result is OK is judged. In the casewhere Result is NG, the processing operation proceeds to step S464. Inthe case where Result is OK, the processing operation proceeds to stepS472. At the step S472, processing for adding (supplementing) ASEL_SDU(i.e., AAL-SDU) into the receiving buffer is executed. Further, at stepS473, the preparation processing of AAL0 parameter is executed. Thedetail of this processing will be described later with reference to theflowchart of FIG. 53.

Then, the processing operation proceeds to step S474, at whichMASEL_DATA.Ind is outputted to ASEL layer management of FIG. 6. In thisMASEL_DATA.Ind, ASEL-UNI ID, VPI/VCI value, AAL-ID (SDU), AAL-LP,AAL-CI, AAL-ES are included. Thereafter, there results the originalstatus for a second time (the system control status returns to theoriginal status).

At step S475, the composing processing of AAL0 (LM data) is executed.The detail of this processing will be described later with reference tothe flowchart of FIG. 51. Then, the processing operation proceeds tostep S476, at which whether or not Result is OK is judged. In the caseof NG, the processing operation proceeds to step S465. In the case ofOK, the processing operation proceeds to step S477, at which processingfor adding (supplementing) ASEL_SDU (i.e., ASEL_CMP) into the receivingbuffer is executed. Then, the processing operation proceeds to stepS478, at which local event to instruct reception of ASEL_CMP message isissued. Thereafter, there results the original status for a second time(the system control status returns to the original state).

At step S479, composing processing of AAL5 is executed. The detail ofthis processing will be described later with reference to the flowchartof FIG. 49. Then, the processing operation proceeds to step S480, atwhich whether or not Result is OK is judged. In the case where Result isOK, the processing operation proceeds to step S481, at which theprocessing for adding (supplementing) ASEL_SDU (i.e., AAL-SDU beingcomposed) into the receiving buffer is executed. Then, at step S482,whether MR is either 0 or 1 is judged. In the case where MR is zero (0),the processing operation proceeds to step S483, at which the preparationprocessing of the AAL5 parameter is executed. The detail of thisprocessing will be described later with reference to the flowchart ofFIG. 52. Then, at step S484, AAL_UNIDATA.Ind is outputted to Upper Layerof FIG. 6. In this AAL_UNIDATA.Ind, ASEL-UNI ID, VPI/VCI value,AAL-ID(SDU), AAL-LP, AAL-CI, AAL-UU, AAL-ES are included. Thereafter,there results the original status for a second time (the system controlstatus returns to the original status).

In the case where it is judged at step S482 that value of MR is 1, theprocessing of steps S483, S484 are skipped.

On the other hand, in the case where it is judged at step S480 thatResult is NG, the processing operation proceeds to step S485, at whichwhether value of MR is either 0 or 1 is judged. In the case where it isjudged at the step S485 that MR is 1, the processing operation proceedsto the step 465. In the case where it is judged that MR is 0, theprocessing operation proceeds to step S486, at which 0 is set withrespect to Rov_(—ER)_Flag. This parameter represents that any error isincluded in AAL-SDU being received, and has independence values everyrespective ASEL-VCCs.

Then, the processing operation proceeds to step S487, at which No erroris set with respect to Rov_ER_Status.

Then, the processing operation proceeds to step S487A, at which valueobtained by incrementing value of SN by 1 is set with respect toNext_Rov_SN. This parameter indicates SN value expected next at thereceiving side. This parameter is incremented by module 128 and hasindependent values every ASEL-VCCs.

Then, the processing operation proceeds to the step S465, at which theprocessing for disusing (aborting) ASEL-PDU is executed. At the stepS466, OK is set with respect to Result. Thereafter, there results theoriginal status for a second time the system control status returns tothe original status).

On the other hand, when input of LK_ISO.Ind is received from the 1394Link layer of FIG. 6 at step S488 in an arbitrary status, processing ofstep S489 and those subsequent thereto are executed. In theabove-mentioned example, in this LK_ISO.Ind, 1394 Bus Index, IsochronousChannel number, Tag value, Data Length, Data (ASEL-PDU), Speed, Packetstatus, etc. are included.

At the step S489, check processing of 1394 Isochronous header format iscarried out. The detail of this processing will be described later withreference to the flowchart of FIG. 48. Then, the processing operationproceeds to step S490, at which whether or not Result is OK is judged.In the case where Result is NG, the processing operation proceeds to thestep S465. Thus, the processing the step S465 and steps subsequentthereto will be executed.

On the contrary, in the case where it is judged that Result is OK, theprocessing operation proceeds to step S491, at which the retrievalprocessing of ASEL-UNI ID using 1394 Bus Index, Isochronous Channelnumber and Tag value is executed. At step S492, whether or not ASEL-UNIID is retrieved is judged. In the case where ASEL-UNI ID is retrieved,the processing operation proceeds to step S493, at which check ofVPI/VCI value of ASEL header is carried out. In the case where thisvalue is correct, the processing operation proceeds to step S457. Thus,the processing of the step S457 and steps subsequent thereto will beexecuted.

In the case where it is judged at the step S492 that ASEL-UNI ID is notretrieved, or in the case where it is judged at the step S493 that valueof VPI/VCI value is not correct, the processing operation proceeds tothe step S465. Thus, the processing of the step S465 and stepssubsequent thereto will be executed.

Explanation will now be given with reference to the flowcharts of FIGS.47 to 53 in connection with the more detailed processing of thesubroutine represented by the processing of FIGS. 44 to 46.

FIG. 47 shows the detail of the check processing of 1394 Asynchronousheader format at the step S452 of FIG. 44. Initially, at step S501,whether or not 1394 header CRC error takes place is judged. In the casewhere such error does not take place, the processing operation proceedsto step S502, at which whether or not value of Destination Offset isequal to value of aselLayer1394DestOffset is judged. In the case wherevalues of the both are equal to each other, the processing operationproceeds to step S503, at which whether or not Transaction Code is 1 isjudged. In the case where this value is 1, the processing operationproceeds to step S504, at which whether or not Retry Code is 1 isjudged. In the case where this value 1, the processing operation furtherproceeds to step S505, at which whether or not Packet status isFORMAT_ERROR is judged. At this time, in the case where judgment of Nois carried out, the processing operation proceeds to step S506.

When it is judged at the step S501 that error takes place, it is judgedat the step S502 that Destination Offset is not equal toaselLayer1394DestOffset, it is judged at the step S503 that value ofTransaction Code is not 1, it is judged at the step S504 that Retry Codeis not 1, or it is judged at the step S505 that Packet status isFORMAT_ERROR, the processing operation proceeds to step S515, at whichNG is set with respect to Result.

At step S506, whether or not Packet status is BROADCAST is judged. Atthis time, in the case where judgment of Yes is carried out, theprocessing operation proceeds to step S516, at which OK is set withrespect to Result.

In the case where judgment of No is carried out at the step S506, theprocessing operation proceeds to step S507, at which whether or notPacket status is DATA_CRC_ERROR is judged. At this time, in the casewhere judgment of No is carried out, the processing operation proceedsto step S508, at which OK is set with respect to Result. Then, at stepS509, 1 is set with respect to Acknowledge (there is caused to resultstatus of ack₁₃ complete). At step S510, RELEASE is set with respect toBus Occupancy control. At step S511, value of aselVccOprSpeed is setwith respect to Speed. Further, at step S512, LK_DATA.resp is outputtedto the 1394 Link layer of FIG. 6. In this case, in this LK_DATA.resp,1394 Bus Index, Acknowledge, Bus Occupancy Control, Speed are included.

On the other hand, in the case where it is judged at the step S507 thatPacket status is DATA_CRC_ERROR, the processing operation proceeds tostep S513, at which the processing for disusing (aborting) Asynchronouspacket is executed. Further, at step S514, 0xD is set with respect toAcknowledge (ack_data_error is caused to result). Then, the processingoperation proceeds to step S515, at which NG is set with respect toResult.

FIG. 48 shows the detail of the check processing of the 1394 Isochronousheader format at the step S489 of FIG. 44. Initially, at step S521,whether or not error takes place at the 1394 header CRC is judged. Inthe case where no error takes place, the processing operation proceedsto step S522, at which whether or not DATA_CRC_ERROR is set with respectto Packet status is judged. At this time, in the case where judgment ofNo is carried out, the processing operation proceeds to step S523, atwhich whether or not FORMAT_ERROR is set at (with respect to) Packetstatus is judged. At this time, in the case where judgment of No iscarried out, the processing operation proceeds to step S524, at which OKis set at (with respect to) Result.

On the contrary, in the case where it is judged at the step S521 thatany error takes place at 1394 header CRC, in the case where it is judgedat the step S522 that DATA_CRC_ERROR is set with respect to Packetstatus, or in the case where it is judged at the step S523 thatFORMAT_ERROR is set at (with respect to) Packet status, the processingoperation proceeds to step S525, at which NG is set with respect toResult.

FIG. 49 shows the detail of the composing processing of AAL5 at the stepS479 of FIG. 46. At step S541, whether Rcv_ER_Flag is either 0 or 1 isjudged. In the case where it is judged that Rcv_ER_Flag is 1, theprocessing operation proceeds to step S552, at which NG is set withrespect to Result.

On the contrary, in the case where it is judged at the step S541 thatRcv_ER_Flag is zero (0), the processing operation proceeds to step S542,at which whether or not EI is 1 is judged. In the case where EI is not1, the processing operation proceeds to step S543, at which whether ornot aselVccReceiveSeqUse is Use is judged. In the case where it isjudged that aselVccReceiveSeqUse is Use, the processing operationproceeds to step S544, at which whether or not SN is Next_Rcv_SN isjudged.

In the case where judgment of Yes is carried out at the step S544, theprocessing operation proceeds to step S545, at which Next_Rcv_SN isincremented. Then, the processing operation proceeds to step S546. Inthe case where it is judged at the step S543 that aselVccReceiveSeqUseis not (in) Use (state), the processing of the step S544 and the stepS545 are skipped. Thus, the processing operation proceeds to step S546.

At the step S546, value obtained by subtracting 8 from Data Length isadded to Sum_AAL_SDU_Len. This parameter indicates the length ofcomposed AAL-SDU being received, and has independent values everyrespective ASEL-VCCs.

Then, the processing operation proceeds to step S547, at which whetheror not aselAal5ConnReceiveMaxSduSize is smaller than Sum_AAL_SDU_Len isjudged. At this time, in the case where judgment of No is carried out,OK is set with respect to Result at step S548. In the case wherejudgment of Yes is carried out at the step S547, the processingoperation proceeds to step S549, at which 1 is set with respect toRcv_ER_Flag. Further, at step S550, the processing for disusing(aborting) AAL-ADU being composed is carried out. At step S551, NG isset with respect to Result.

In the case where it is judged at the step S544 that SN is not equal toNext_Rcv_SN, the processing operation proceeds to step S555, at whichAAL-SDU Length Error is set at (with respect to) Rcv_ER_Status. At stepS556, whether or not aselAal5ConnErSduDeliver is Allow is judged. In thecase where aselAal5ConnErSduDeliver is Allow, the processing operationproceeds to step S557, at which processing for preserving (storing)Next_Rcv_SN and SN value in the received ASEL-PDU header into the SNerror list is executed. Then, at step S558, value obtained by adding 1to SN is set with respect to Next_RcvQSN. Thereafter, the processingoperation proceeds to step S546. Thus, the processing of the step S546and steps subsequent thereto will be executed.

In the case where it is judged at the step S556 thataselAal5ConnErSduDeliver is not Allow, the processing operation proceedsto step S559, at which 1 is set with respect to Rcv_ER_Flag. At stepS560, the processing for disusing (aborting) AAL-SDU being composed isexecuted. Then, at step S561, NG is set with respect to Result.

In the case where it is judged at the step S542 that EI is 1, theprocessing operation proceeds to step S553, at which whether ER-ID isCPCS-SDU Length error or CPCS CRC error is judged. In the case of theformer, the processing operation proceeds to step S555. Thus, theprocessing of the step S555 and steps subsequent thereto will beexecuted. In the case of the latter, the processing operation proceedsto step S554, at which AAL-SDU CRC Error is set with respect toRcv_ER_Status. Thereafter, the processing operation proceeds to stepS556. Thus, the processing of the step S556 and steps subsequent theretowill be executed.

FIG. 50 shows the detail of the composing processing of AAL0 (User data)at the step S459 of FIG. 45. At step S581, whether or not EI is 1 isjudged. In the case where EI is not 1, the processing operation proceedsto step S582, at which whether or not aselVccReceiveSeqUse is Use isjudged. In the case where aselVccReceiveSeqUse is Use, the processingoperation proceeds to step S583, at which whether or not SN is equal toNext_Rcv_SN is judged. At this time, in the case where judgment of Yesis carried out, the processing operation proceeds to step S584, at whichthe value of Next_Rcv_SN is incremented.

In the case where it is judged at the step S582 thataselVccReceiveSeqUse is not Use, the processing of the steps S583, S584are skipped. Thus, the processing operation proceeds to step S585.

At the step S585, value obtained by subtracting 8 from Data Length isset with respect to Sum_AAL_SDU_Len. Then, at step S586, whether or notSum_AAL_SDU_Len is greater than 48 is judged. At this time, in the casewhere judgment of No is carried out, the processing operation proceedsto step S587, at which OK is set with respect to Result. On thecontrary, in the case where judgment of Yes is carried out at the stepS586, the processing operation proceeds to step S588, at whichprocessing for disusing (aborting) AAL-SDU being composed is carriedout. Then, the processing operation proceeds to step S589, at which NGis set with respect to Result.

In the case where it is judged at the step S583 that value of SN is notequal to value of Next_Rcv_SN, the processing operation proceeds to stepS595, at which value obtained by incrementing value of SN by 1 is setwith respect to Next_Rcv_SN. Then, the processing operation proceeds tostep S585. Thus, the processing of the step S585 and steps subsequentthereto will be executed.

In the case where it is judged at step S581 that EI is 1, the processingoperation proceeds to step S590, at which whether ER-ID is CPCS-SDULength Error or CPCS CRC error is judged. In the case of the former, theprocessing operation proceeds to step S591, at which AAL-SDU LengthError is set with respect to Rcv_ER_Status. Then, the processingoperation proceeds to step S593, at which whether or notaselAal0ConnErSduDeliver is Allow is judged. In the case whereacelAal0ConnErSduDeliver is Allow, the processing operation proceeds tostep S594, at which processing for preserving (storing) Next_Rcv_SN andSN value in the received ASEL-PDU header into the SN error list isexecuted. Then, the processing operation proceeds to step S595. Thus,the processing of the step S595 and steps subsequent thereto will beexecuted. On the contrary, in the case of the latter, the processingoperation proceeds to step S592, at which AAL-SDU CRC Error is set withrespect to Rcv_ER_Status. Thereafter, the processing operation proceedsto step S593.

In the case where it is judged at the step S593 thataselAal0ConnErSduDeliver is not Allow, the processing operation proceedsto step S596, at which processing for disusing (aborting) AAL-SDU beingcomposed is executed. Further, at step S597, NG is set with respect toResult.

FIG. 51 shows the detail of AAL0 (LM data) composing processing at thestep S470 and the step S475 of FIG. 45. At step S611, whether or not EIis 1 is judged. In the case where EI is not 1, the processing operationproceeds to step S612, at which whether or not aselVccReceiveSeqUse isUse is judged. In the case where aselVccReceiveSeqUse is Use, theprocessing operation proceeds to step S613, at which whether or not SNis equal to value obtained by subtracting 1 from Next_Rcv_SN is judged.In the case where it has been judged that both values are equal to eachother, the processing operation proceeds to step S614, at which valueobtained by subtracting 8 from Data Length is set with respect toSum_AAL_SDU_Len.

Then, at step S615, whether or not Sum_AAL_SDU_Len is greater than 48 isjudged. At this time, in the case where judgment of No is carried out,the processing operation proceeds to step S616, at which OK is set withrespect to Result. On the contrary, in the case where judgment of Yes iscarried out at the step S615, the processing operation proceeds to stepS617, at which the processing for disusing (aborting) AAL-SDU beingcomposed is executed. Then, the processing operation proceeds to stepS618, at which NG is set with respect to Result.

In the case where it is judged at the step S612 thatacelVccReceiveSeqUse is not Use, the processing operation proceeds tostep S614. Thus, the processing of the step S614 and steps subsequentthereto will be executed.

In the case where it is judged at the step S613 that SN is not equal tovalue obtained by subtracting 1 from Next_Rcv_SN, the processingoperation proceeds to step S623A, at which value obtained byincrementing value of SN by 1 is with respect to Next_Rcv_SN.Thereafter, the processing operation proceeds to step S614. Thus, theprocessing of the step S614 and steps subsequent thereto will beexecuted.

In the case where it is judged at the step S611 that EI is 1, theprocessing operation proceeds to step S619, at which whether ER-ID iseither CPCS-SDU Length error or CPCS CRC error is judged. In the casewhere it is judged that ER-ID is the former, the processing operationproceeds to step S620, at which AAL-SDU Length Error is set with respectto Rcv_ER_Status. Then, the processing operation proceeds to step S622,at which whether or not aselAal0ConnErSduDeliver is Allow is judged. Inthe case where it is judged that aselAsl0ConnErSduDeliver is Allow, theprocessing operation proceeds to step S623, at which processing forpreserving (storing) Next_Rcv_SN and SN value in the received ASEL-PDUheader into the SN error list is executed. Thereafter, the processingoperation proceeds to step S623A. Thus, the processing of the step S623Aand steps subsequent thereto will be executed. On the contrary, in thecase where it is judged that ER-ID is the latter, the processingoperation proceeds to step S621, at which AAL-SDU CRC Error is set withrespect to Rcv_ER_Status. Thereafter, the processing operation proceedsto step S622.

In the case where it is judged at the step S622 thataselAal0ConnErSduDeliver is not Allow, the processing operation proceedsto step S624, at which processing for disusing (aborting) AAL-SDU beingcomposed is executed. Then, NG is set with respect to Result at stepS625.

FIG. 52 shows the detail of the processing for preparing AAL5 parameterat the step S483 of FIG. 46. At step S641, LP is set with respect toAAL-LP. This parameter is caused to undergo mapping with respect to AAL5specific field of ASEL-PDU header. Then, the processing operationproceeds to step S642, at which CI is set with respect to AAL-CI. Thisparameter is also caused to undergo mapping with respect to AAL5specific field of ASEL-PDU header.

Then, the processing operation proceeds to step S643, at whichRcv_ER_Status is set with respect to AAL-ES. Further, at step S644,CPCS-UU is set with respect to AAL-UU.

FIG. 53 shows the detail of the processing for preparing AAL0 parameterat the step S462 and the step S473 of FIG. 45. At step S651, LP is setwith respect to AAL-LP. This parameter is caused to undergo mapping withrespect to AAL0 specific field of ASEL-PDU header. Then, at step S652,CI is set with respect to AAL-CI. This parameter is also caused toundergo mapping with respect to AAL0 specific field of ASEL-PDU header.Then, at step S653, Rcv_ER_Status is set with respect to AAL-ES.

In the case where ASEL as described above is used to carry outcommunication between the ATM terminal 1 and the 1394 terminals 4, 22,23 shown in FIG. 4 by using IP/ATM as the standard protocol similarly tothe conventional case, protocol stacks of U (User) plane and C (Control)plane of end to end are caused to respectively undergo layout as shownin FIGS. 54 and 55.

As shown in FIG. 54, the protocol stack of the U plane of the ATMterminal 1 consists of PHY (Physical) layer, ATM layer, AAL5 layer,IP/ATM layer and IP layer, and the protocol stack of the U plane of theATM network 2 consists of PHY layer and ATM layer.

The protocol stack of the U plane of the ATM/1394 repeaters 3, 21consists, at the ATM network side, PHY layer, ATM layer and AAL5 layer,and consists, at the 1394 terminal side, 1394 PHY layer, 1394 LINK layerand ASEL layer 31. The protocol stack of the U plane of the 1394terminals 4, 22, 23 consists of 1394 PHY layer, 1394 LINK layer, ASELlayer 32, IP/ATM layer and IP layer.

Between the ATM/1394 repeater 3 and the 1394 terminal 4, and between theATM/1394 repeater 21 and the 1394 terminals 22, 23, AAL/ATM is caused toundergo emulation by ASEL 31, and the concept of VPC/VCC thus exists.For this reason, handling of packet of the U plane can be carried out byVPI/VCI value in place of IP. This VPI/VCI is ordinarily included in thedescriptor table of AAL-PDU, but is not included in packet as in thecase of interface data. As a result, when ASEL 31 carries out routing,it is unnecessary to copy the content (interface data) of packet.Accordingly, in the ATM/1394 repeaters 3, 21, burden (load) is lessened,and throughput of the ATM/1394 repeaters 3, 21 can be improved.

Moreover, as shown in FIG. 55, the protocol stack of the C plane of theATM terminal 1 consists of PHY layer, ATM layer, AAL5 layer,SSCF(ITU-TQ. 2130)+SSCOP(ITU-TQ. 2110) layer, and Q.2931(ITU-TQ. 2931)layer. The protocol stack of the C plane of the ATM network 2 is of astructure similar to the case of the ATM terminal 1.

The protocol stack of the C plane of the ATM/1394 repeaters 3, 21 is ofa structure at the ATM network side which is similar to the case of theATM terminal 1 and the ATM network 2. On the other hand, the 1394terminal side is of a structure similar to the protocol stack of the1394 terminals 4, 22, 23, and consists of 1394 PHY layer, 1394 LINKlayer and ASEL layer 33 (corresponding to the ASEL layer 31 of FIG. 54).The protocol stack of the C plane of the 1394 terminals 4, 22, 23consists of 1394 PHY layer, 1394 LINK layer, ASEL layer 34(corresponding to the ASEL layer 32 of FIG. 54), SSCF+SSCOP layer, andQ. 2931 layer.

Between the ATM/1394 repeater 3 and the 1394 terminal 4, and between theATM/1394 repeater 21 and the 1394 terminals 22, 23, known signalingprotocol (Q. 2931 and SSCF+SSCOP) used in UNI (User-Network Interface)of the ATM network 2 can be applied to the layer 35 or the layer 36. Forthis reason, it becomes unnecessary to develop peculiar signalingprotocol from the first stage. As a result, the number of steps requiredfor developing the system can be reduced, and the reliability of thesystem can be improved.

Further, by ASEL, it is possible to provide service by variousapplications of the connection type utilizing multi-point,multi-connection which are the feature of ATM as they are oninfrastructure having elements of low cost, easiness of cabling, andimplementation of effective utilization of resource of media by sharedmedia (media shared type network: various terminals are connected tosingle cable (transmission medium) to carry out communication).

More practical example of the operation in the system of FIG. 4 will befurther explained. As an example, there are taken three kinds ofcommunications of communication between 1394 terminal 22-1 connected toATM/1394 repeater 21 and ATM terminal 1, communication between 1394terminal 22-1 and 1394 terminal 23-1, and communication between 1394terminal 22-1 and 1394 terminal 22-2.

Even in the case where any one of communications is carried out,ASEL-CMEs of User side on all 1394 terminals Broadcast message of WakeUp(FIG. 15), whereby only ASEL-CME of Network side on the ATM/1394repeater 21 receives that message. Thus, ASEL-CMEs of respective 1394terminals inform ASEL-CME of ATM/1394 repeater 21 of the own Node UniqueID and Self ID. It is to be noted that transmission/reception ofASEL-CMP message (FIG. 14) is carried out in a closed manner onlybetween ASEL-CMEs of Network side and User side opposite to each otherthrough ASEL-CMI (FIG. 11), and is terminated by ASEL-CMEs of both ends.For this reason, (control procedure of) such message is not incorporatedin the protocol stacks of FIGS. 54 and 55.

When ASEL-CME of the ATM/1394 repeater 21 receives WakeUp (FIG. 15), itassigns new ASEL-UNI ID thereto to register such ASEL-UNI ID in a mannerrelated to 1394 Bus Index, and Node Unique ID and Self ID of User side.Then, the above-mentioned ASEL-CME transmits ActReq (FIG. 16) toASEL-CMEs of respective 1394 terminals to make request for starting ofrespective ASEL-CMEs of the User side and to make request forregistration of Node Unique ID and Self ID of Network side.

ASEL-CMEs of respective 1394 terminals carry out registration incorrespondence with such request to carry out transition to Activestatus to transmit ActAck (FIG. 17) to ASEL-CME of the ATM/1394 repeater21. Thus, both terminals and the repeater are brought into Activestatus.

When transition to Active status is carried out, MASEL_Act.Ind primitiveis issued with respect to the ASEL layer management from the ASEL-CME.Thus, the ASEL layer management recognizes activated ASEL-UNI ID and1394 Bus Index in which that ASEL-UNI exists. Thus, the above-describedprocessing is carried out between (ASEL-CME of) the repeater 21 and(ASEL-CMEs of) all 1394 terminals connected, whereby the ATM/1394repeater 21 can recognize connection relationship of respective 1394terminals with respect to corresponding 1394 serial buses.

Practical procedure of communication will now be indicated. It is nowassumed that, for setting of VCC, SVC (Switched Virtual Circuit)connection by the protocol stack of FIG. 55 is used, but PVC (PermanentVirtual Circuit) connection is not used. Initially, communicationbetween the 1394 terminal 22-1 connected to the ATM/1394 repeater 21 andthe ATM terminal 1 will be described.

Data which are desired to ultimately undergo transmission/receptionbetween the 1394 terminal 22-1 and the ATM terminal 1 are data on the Uplane as shown in FIG. 54. In order to open (provide) VCC which is theconnection for carrying out transmission/reception of data of this Uplane, the protocol stack of the C plane of FIG. 55 is used.

In order to carry out transmission/reception of the protocol on the Cplane, VPI/VCI ordinarily open (provide) in advance two kinds of VCCsusing 0/5 and 0/16 every respective ASEL-UNIs and respective ATM-UNIs.In addition, ASELs 33, 34 of the ATM/1394 terminal 21 and the 1394terminal 22-1 have a function to convert data of the standard of IEEE1394 into data of the standard of ATM (AAL), and a function to convertdata of the standard of ATM (AAL) into data of the standard of IEEE 1394in a manner opposite to the above.

Thus, as signaling protocols 35, 36 in the ATM/1394 repeater 21 and the1394 terminal 22-1, protocol similar to the ATM terminal 1 and the ATMnetwork 2 can be used. By these signaling protocols, various parameters(VPI/VCI Value, AAL Type, QoS class, Transmit/Receive Bandwidth, etc.)of VCC used in the U plane of FIG. 54 are determined.

Followed by the determination of these VCC parameters, in the ATM/1394repeater 21 and the 1394 terminal 22-1, MASEL_ConSet.req primitive isissued with respect to respective ASEL-CMEs via ASEL layer managementfrom application programs of the signaling protocols 35, 36. In thiscase, the ATM/1394 repeater 21 already recognizes by the signalingprotocols that the ATM terminal 1 which is the terminating point of VCCof one side does not exist in ASEL-UNIs that the ATM terminal 1 contains(accommodates).

In ASEL-CME of User side mounted in the 1394 terminal 22-1, as shown inthe flowchart of FIG. 25, in the case where MASEL_ConSet.req primitiveis received, various parameters included in that primitive are preserved(stored) thereafter to carry out judgment as to whether or not QoS Typeis CBR.

In the case of CBR, IsoReq (FIG. 18) to make request for assignment ofIsochronous channel which solves assigned VPI/VCI is transmitted to theATM/1394 repeater 21 in which ASEL-CME is mounted of Network side.ASEL-CME of the ATM/1394 repeater 21 sends IsoReply (FIG. 19) back tothe ASEL-CME of the 1394 terminal 22-1 to designate Isochronous channelthereat. In this way, Isochronous channel used between the ATM/1394repeater 21 and the 1394 terminal 22-1 is assigned. Thus, communicationchannel (path) in the IEEE 1394 standard is ensured.

In the case except for CBR, DestIDReq (FIG. 20) to make request forvalue of Destination ID of Asynchronous packet which solves assignedVPI/VCI is transmitted to the ATM/1394 repeater 21 in which ASEL-CME ismounted of Network side. The ASEL-CME of the ATM/1394 repeater 21 sendsDestIDRply (FIG. 21) back to the ASEL-CME of the 1394 terminal 22-1.Thereat, Self ID in corresponding 1394 serial bus of the ATM/1394repeater 21 itself which is the destination node is informed. Thus,communication channel (path) in the IEEE 1394 standard is ensured.

By the above-mentioned operation, VCC is opened (provided) between theATM terminal 1 and the 1394 terminal 22-1. Moreover, since ASELs 31, 32of the ATM/1394 repeater 21 and the 1394 terminal 22-1 have a functionto convert data of the standard of IEEE 1394 into data of the standardof ATM(AAL) and a function to convert data of the standard of ATM(AAL)into data of the standard of IEEE 1394 in a manner opposite to theabove, protocol (e.g., IP/ATM) similar to the upper layer of AAL5 in theATM terminal 1 can be used as the upper layer of ASEL 32 in the 1394terminal 22-1.

Explanation will now be given in connection with communication between1394 terminal 22-1 and 1394 terminal 23-1 connected to the ATM/1394repeater 21.

Similarly to the case of communication between the ATM terminal 1 andthe 1394 terminal 22-1, also between the 1394 terminal 22-1 and the 1394terminal 23-1, in order to open (provide) VCC for carryingtransmission/reception of data on the U plane as shown in FIG. 54, theprotocol stack of the C plane of FIG. 55 is used. Further, as signalingprotocols 35, 36 in the ATM/1394 repeater 21, the 1394 terminal 22-1 andthe 1394 terminal 23-1, common protocol can be used. By these signalingprotocols, various parameters (VPI/VCI Value, AAL Type, QoS class,Transmit/Receive Bandwidth, etc.) of VCC used in the U plane of FIG. 54are determined. It is to be noted that signaling protocols 35, 36 arecaused to undergo transmission/reception between the 1394 terminal 22-1and the 1394 terminal 23-1 necessarily through the ATM/1394 repeater 21.

Followed by the determination of these VCC parameters, in the ATM/1394repeater 21, the 1394 terminal 22-1 and the 1394 terminal 23-1,MASEL_ConSet.Req primitive is issued with respect to respectiveASEL-CMEs via the ASEL layer management from application programs of thesignaling protocols 35, 36. It is to be noted that, by the signalingprotocols, the ATM/1394 repeater 21 already recognizes that the 1394terminal 22-1 and the 1394 terminal 23-1 which are terminating points ofboth VCCs exist in ASEL-UNIs that the ATM/1394 repeater 21 itselfcontains (accommodates), but they are connected to 1394 serial busesdifferent from each other.

At ASEL-CMEs of User side mounted in the 1394 terminal 22-1 and the 1394terminal 23-1, similarly to the above-mentioned case, afterMASEL_ConSet.req primitive is received, various parameters are preserved(stored). Thereafter, judgment as to whether or not QoS Type is CBR iscarried out.

In the case of CBR, similarly to the above-mentioned case, respectiveASEL-CMEs of the User side transmits IsoReq (FIG. 18) to make requestfor assignment of Isochronous channel which solves assigned VPI/VCI tothe ATM/1394 repeater 21 in which ASEL-CME is mounted of the Networkside. In response thereto, the ASEL-CME of the ATM/1394 repeater 21sends IsoReply (FIG. 19) back thereto to designate Isochronous channelsthereat. In this case, since those terminals are different 1394 serialbuses, it is possible to respectively independently designateIsochronous channel numbers. In a manner stated above, Isochronouschannels used between the ATM/1394 repeater 21 and the 1394 terminal22-1, and between the ATM/1394 repeater 21 and the 1394 terminal 23-1are assigned. Thus, communication channel (path) in the IEEE 1394standard is ensured.

In the case except for CBR, similarly to the above-mentioned case,respective ASEL-CMEs of the User side transmit DestIDReq (FIG. 20) tothe ATM/1394 repeater 21 in which ASEL-CME is mounted of the Networkside. In response thereto, the ASEL-CME of the ATM/1394 repeater 21sends DestIDRply (FIG. 21) back thereto. Thereat, Self IDs in respective1394 serial buses of the ATM/1394 repeater 21 itself, which are thedestination nodes, are informed. Thus, communication channel (path) inthe IEEE 1394 standard is ensured.

By the above-mentioned operation, VCC is opened (provided) between the1394 terminal 22-1 and the 1394 terminal 23-1 repeating (relaying) theATM/1394 repeater 21. In the above-mentioned example, in this VCC, ASEL31 of the ATM/1394 repeater 21 carries out repeat (replay) operation ofdata caused to undergo transmission/reception between the 1394 terminal22-1 and the 1394 terminal 23-1 by using the function to convert data ofthe standard of the IEEE 1394 into data of the standard of ATM(AAL), andthe function to convert data of the standard of ATM(AAL) into data ofthe standard of the IEEE 1394 in a manner opposite to the above.

Subsequently, explanation will be given in connection with communicationbetween the 1394 terminal 22-1 and the 1394 terminal 22-2 connected tothe ATM/1394 repeater 21.

Also in this case, in order to open (provide) VCC for carrying outtransmission/reception of data on U-plane as shown in FIG. 54, theprotocol stack of the C plane of FIG. 55 is used. Further, as signalingprotocols 35, 36 in the ATM/1394 repeater 21, the 1394 terminal 22-1 andthe 1394 terminal 22-2, common protocol can be used. By these signalingprotocols, various parameters (VPI/VCI Value, AAL Type, QoS class,Transmit/Receive Bandwidth, etc.) of VCC used in the U plane of FIG. 54are determined. It is to be noted that the signaling protocols 35, 36are caused to undergo transmission/reception between the 1394 terminal22-1 and the 1394 terminal 22-2 necessarily through the ATM/1394repeater 21.

Followed by the determination of these VCC parameters, in the ATM/1394repeater 21, the 1394 terminal 22-1 and the 1394 terminal 22-2,MASEL_ConSet.req primitive is issued with respect to respectiveASEL-CMEs via ASEL layer management from application programs of thesignaling protocols 35, 36. In this case, by the signaling protocols,the ATM/1394 repeater 21 already recognizes that the 1394 terminal 22-1and the 1394 terminal 22-2 which are terminating points of both VCCsexist in ASEL-UNIs that the ATM/1394 repeater 21 itself contains(accommodates) and are connected to the same 1394 serial bus. Thus,since it is unnecessary to carry out repeat (relay) operation in regardto data on this VCC, VCC which can be caused to directly undergotransmission/reception of data between the 1394 terminal 22-1 and the1394 terminal 22-2 is opened (provided).

At ASEL-CMEs of User side mounted in the 1394 terminal 22-1 and the 1394terminal 22-2, similarly to the above, various parameters ofMASEL_ConSet.req primitive are preserved (s_ored). Thereafter, judgmentas to whether or not QoS Type is CBR is carried out.

In the case of CBR, similarly to the above, respective ASEL-CMEs of theUser side transmit IsoReq (FIG. 18) to the ATM/1394 repeater 21 in whichASEL-CME is mounted of Network side. In response thereto, the ASEL-CMEof the ATM/1394 repeater 21 sends IsoReply (FIG. 19) back thereto todesignate Isochronous channel thereat. In this case, the sameIsochronous channel number is designated with respect to respectiveASEL-CMEs of the User side. In this instance, a way of use may beemployed to designate Tag Value corresponding to the high order 2 bitsof the assigned Isochronous channel so as to take (0, 1) to therebydisplay that corresponding channel is the channel that only ASEL 32 ofUser side receives. In this way, Isochronous channel used between the1394 terminal 22-1 and the 1394 terminal 22-2 is assigned. Thus,communication channel (path) in the IEEE 1394 standard permitted todirectly undergo transmission/reception of data is ensured.

In the case except for CBR, similarly to the above, respective ASEL-CMEsof the User side transmit DestIDReq (FIG. 20) to the ATM/1394 repeater21 in which ASEL-CME is mounted of Network side. In response thereto,the ASEL-CME of the ATM/1394 repeater 21 sends DestIDRply (FIG. 21) backthereto. Thereat, the 1394 terminal 22-1 is informed of Self ID of the1394 terminal 22-2 which is the destination node, and the 1394 terminal22-2 is informed of Self ID of the 1394 terminal 22-1 which is thedestination node. Thus, communication channel (path) in the IEEE 1394standard permitted to directly undergo transmission/reception of data isensured.

By the above-mentioned operation, VCC is directly opened (provided)between the 1394 terminal 22-1 and the 1394 terminal 22-2 withoutrepeating (relaying) the ATM/1394 repeater 21. It is to be noted that,in this VCC, ASEL 31 of the ATM/1394 repeater 21 is not concerned withdata caused to undergo transmission/reception between the 1394 terminal22-1 and the 1394 terminal 23-1.

It is to be noted that since connection control primitive group(MASEL_ConSet.req, MASEL_ConRec.req, MASEL_ConSet.conf,MASEL_ConRel.req, MASEL_ConRel.conf) are included in the primitives forASEL layer management, those primitives are issued via the ASEL layermanagement. However, by selecting actual software installing method, itis also possible as a matter of course to employ, e.g., embodiments suchthat those primitives are issued directly from application programs ofthe signaling protocols 35, 36, or are issued directly from thesignaling protocols 35, 36 themselves.

In addition, while single ATM terminal is connected to the ATM networkin the above-described embodiments, plural ATM terminals may beconnected to the ATM network so that respective 1394 terminals acceptoffer of desired data from the plural ATM terminals.

INDUSTRIAL APPLICABILITY

In accordance with the communication control equipment and thecommunication control method according to this invention, since such anapproach is employed to convert data of the second transmission standardreceived through the repeater into data of the first transmissionstandard, and to convert predetermined data of the first transmissionstandard into data of the second transmission standard, the existingsignaling protocol used in accordance with the first transmissionstandard can be applied. Thus, the number of development steps of thesystem can be reduced, and the reliability can be improved.

In accordance with the communication control equipment and thecommunication control method according to this invention, since such anapproach is employed to process, by the same signaling protocol as thesignaling protocol used at the first terminal, data of the firsttransmission standard transmitted from the first terminal and dataconverted into data of the first transmission standard from the secondtransmission standard, which has been transmitted from the secondterminal, the number of development steps of the system and thereliability can be improved.

In accordance with the communication control equipment and thecommunication control method according to this invention, since such anapproach is employed to convert data of the first transmission standardtransmitted from the first terminal into data of the second transmissionstandard, and to convert data of the second transmission standardtransmitted from the second terminal into data of the first transmissionstandard; and to carry out, at the second terminal, a processing toconvert data of the second transmission standard which has been causedto undergo transmission (transmitted) through the repeater into data ofthe first transmission standard, and to convert predetermined data ofthe first transmission standard into data of the second transmissionstandard, routing can be carried out only by connection information inthe first transmission standard. For this reason, burden (load) of therepeater can be lessened. In addition, the conventional signalingprotocol used in accordance with the first transmission standard can beapplied between the repeater and the second terminal. Thus, the numberof development steps of the system can be reduced and the reliabilitycan be improved.

In accordance with the communication control equipment and thecommunication control method according to this invention, sincecommunication channel (path) for transferring data of the transmissionstandard that the terminal and any other terminal carry outtransmission/reception is set in advance by using predetermined controlcommands therebetween through the repeater or directly therebetween,burden (load) of the repeater can be lessened. In addition, transfer ofdata can be made substantially without intervention of the repeater.

What is claimed is:
 1. A reception-side terminal adapted for receiving,through a repeater, data transmitted from a transmitting-side terminalthat operates in accordance with a conventional signaling protocol, andfor transmitting predetermined data to the predeterminedtransmitting-side terminal through the repeater, the reception-sideterminal comprising: first converting means for converting data of asecond transmission standard received through the repeater into data ofa first transmission standard; second converting means for convertingpredetermined data of the first transmission standard into data of thesecond transmission standard; and processing means for processing dataof the first transmission standard according to the conventionalsignaling protocol of a higher level in a reception-side protocol stackthan the second transmission standard, so as to avoid a requirement fora special-purpose signaling protocol at the higher level in thereception-side protocol stack.
 2. the reception-side terminal as setforth in claim 1, wherein: the processing means is included in a C(control) plane of the reception-side protocol stack.
 3. Thereception-side terminal as set forth in claim 1, wherein: the firsttransmission standard is a standard of ATM; and the second transmissionstandard is a standard of IEEE
 1394. 4. A communication control methodfor receiving in a reception-side terminal, data transmitted through arepeater from a transmitting-side terminal that operates in accordancewith a conventional signaling protocol, and for transmittingpredetermined data to the transmitting-side terminal through therepeater, the method comprising: a first step of converting data of afirst transmission standard received through the repeater into data of asecond transmission standard, the first converting step occurring at thereception-side terminal; a second step of converting data of the secondtransmission standard into data of the first transmission standard, thesecond converting step occurring at the reception-side terminal; andprocessing data of the first transmission standard according to theconventional signaling protocol of a higher level in a reception-sideprotocol stack than the second transmission standard, so as to avoid arequirement for a special-purpose signaling protocol at the higher levelin the reception-side protocol stack.
 5. A repeater adapted forrepeating, to a reception-side terminal, data transmitted from atransmitting-side terminal having a conventional signaling protocol, andfor repeating, to the transmitting-side terminal, data transmitted fromthe reception-side terminal, thus to control communication between thetransmitting-side terminal and the reception-side terminal, the repeatercomprising: first converting means for converting data of a firsttransmission standard transmitted from the transmitting-side terminalinto data of a second transmission standard; second converting means forconverting data of the second transmission standard transmitted from thereception-side terminal into data of the first transmission standard;and processing means for processing data of the first transmissionstandard according to the conventional signaling protocol of a higherlevel in a repeater protocol stack than the second transmissionstandard, so as to avoid a requirement for a special-purpose signalingprotocol at the higher level in the repeater protocol stack.
 6. Therepeater as set forth in claim 5, further comprising: means forrepeating the data of the first transmission standard to a plurality ofreception-side terminals connected to respective paths, by converting tothe second transmission standard.
 7. The repeater as set forth in claim5, further comprising: means for repeating the data of the secondtransmission standard received from a plurality of second terminals onplural paths, by converting to the first transmission standard.
 8. Acommunication control method, implemented in a repeater, for repeating,to a reception-side terminal, data transmitted from a transmitting-sideterminal having a conventional signaling protocol, and for repeating, tothe transmitting-side terminal, data transmitted from the reception-sideterminal, thus to control communication between the transmitting-sideterminal and the reception-side terminal, the method comprising: a firstconversion step of converting data of a first transmission standardtransmitted from the transmitting-side terminal into data of a secondtransmission standard, the first conversion step performed by arepeater; a second conversion step of converting data of the secondtransmission standard transmitted from the reception-side terminal intodata of the first transmission standard, the second conversion stepperformed by the repeater; and a processing step of processing the dataof the first transmission standard according to the conventionalsignaling protocol of a higher level in a repeater protocol stack thanthe second transmission standard, so as to avoid a requirement for aspecial-purpose signaling protocol at the higher level in the repeaterprotocol stack, the processing step performed by the repeater.
 9. Thereception-side terminal as set forth claim 3, wherein: the first andsecond converting means are part of an ATM over IEEE 1394 serial busemulation layer.
 10. The reception-side terminal as set forth claim 1,wherein: the conventional signaling protocol includes Q.2931 andSSCF+SSCOP.
 11. The method as set forth claim 4, wherein: the processingstep is performed in a C (control) plane of the reception-side protocolstack.
 12. The method as set forth claim 4, wherein: the firsttransmission standard is a standard of ATM; and the second transmissionstandard is a standard of IEEE
 1394. 13. The method as set forth claim12, wherein: the first and second converting steps are performed by anATM over IEEE 1394 serial bus emulation layer.
 14. The method as setforth claim 4, wherein: the conventional signaling protocol includesQ.2931 and SSCF+SSCOP.
 15. The repeater as set forth claim 5, wherein:the processing means is included in a C (control) plane of thereception-side protocol stack.
 16. The repeater as set forth claim 5,wherein: the first transmission standard is a standard of ATM; and thesecond transmission standard is a standard of IEEE
 1394. 17. Therepeater as set forth claim 16, wherein: the first and second convertingmeans are part of an ATM over IEEE 1394 serial bus emulation layer. 18.The repeater of claim 5, wherein: the conventional signaling protocolincludes Q.2931 and SSCF+SSCOP.
 19. The method as set forth claim 8,further comprising: the processing step is performed in a C (control)plane of the reception-side protocol stack.
 20. The method as set forthclaim 8, further comprising: repeating the data of the firsttransmission standard to a plurality of reception-side terminalsconnected to respective paths, by converting to the second transmissionstandard.
 21. The method as set forth in claim 8, further comprising:repeating the data of the second transmission standard received from aplurality of second terminals on plural paths, by converting to thefirst transmission standard.
 22. The method as set forth claim 8,wherein: the first transmission standard is a standard of ATM; and thesecond transmission standard is a standard of IEEE
 1394. 23. The methodas set forth claim 22, wherein: the first and second converting stepsare performed by an ATM over IEEE 1394 serial bus emulation layer. 24.The method as set forth claim 8, wherein: the conventional signalingprotocol includes Q.2931 and SSCF+SSCOP.